The initial speed of a cannon ball is 0.20 km/s. If the ball is to strike a target that is at a horizontal distance of 3.0 km from the cannon, what is the minimum time of flight for the ball?
عرض للطباعة
The initial speed of a cannon ball is 0.20 km/s. If the ball is to strike a target that is at a horizontal distance of 3.0 km from the cannon, what is the minimum time of flight for the ball?
The initial speed of a cannon ball is 0.20 km/s. If the ball is to strike a target that is at a horizontal distance of 3.0 km from the cannon, what is the minimum time of flight for the ball?
A ball is thrown horizontally from the top of a building 0.10 km high. The ball strikes the ground at a point 65 m horizontally away from and below the point of release. What is the speed of the ball just before it strikes the ground?
بارك الله فيكم استاذنا الفاصل ابو جمال
وأثابكم الله خيري الدنيا والاخرة ع هذا المجهود الكبير والذي من الصعب وصفه
وكل يوم يزداد الموضوع ميزة جديدة وفائدة اكبر من اليوم السابق له ولعلها تكون بداية لاشبه ما يكون دورات او محاضرات او حتى تطبيقات ع تخصص ما في الفيزياء وهذا ما نرجو تواجده في منتدانا لما له من فائدة كبيرة لطلبة العلم القائم منتدانا ع خدمتهم ف الاصل
بالطبع فكرتم واضحة ونتفق معكم فيها وبارك الله فيكم فهو نعم الرأياقتباس:
ثالثا : لا احبذ باي حال من الاحوال طلب عضوا بعينه ليقوم بالحلول او مراجعتها لانه ليس شرطا ان يكون هذا العضو على علم ودراية تامه بهذه المسائل وقد لا يستطيع حلها !! ، وبهذا تضيع فرصة ان يقوم عضو آخر على علم ودرايه بحل هذه المسائل ولكنه لا يتقدم للحل بحكم انها موجهة لشخص ما وباسمه ، وارجو ان تكون فكرتي واضحه بهذا الشان .
ولا اضافة ع ذكرتم ولكن تأكيدا ع كلامكم ....فكل عضو عليه طرح كل ما يحتاج اليه من اسئلة ومجال الاجابة ليس قاصر ع عضو بعينه وانما موجه للجميع طالما عنده العلم والوقت ما يستطيع ان يقدمهم لخدمة المسلمين
ويُفضل لو كانت الاسئلة تخص مسائل في الميكانيكا ان توضع هنا في هذا الموضوع المثبت
وجزاكم الله كل خير ع كل ما تقدمونه ع صفحات منتدانا
A baseball is hit at ground level. The ball is observed to reach its maximum height above ground level 3.0 s after being hit. And 2.5 s after reaching this maximum height, the ball is observed to barely clear a fence that is 97.5 m from where it was hit. How high is the fence?
a. 8.2 m b. 15.8 m c. 13.4 m d. 11.0 m
e. 4.9 m
11. A rock is projected from the edge of the top of a building with an initial velocity of 12.2 m/s at an angle of 53° above the horizontal. The rock strikes the ground a horizontal distance of 25 m from the base of the building. Assume that the ground is level and that the side of the building is vertical. How tall is the building?
a. 25.3 m b. 29.6 m c. 27.4 m d. 23.6 m
e. 18.9 m
12. A projectile is thrown from the top of a building with an initial velocity of 30 m/s in the horizontal direction. If the top of the building is 30 m above the ground, how fast will the projectile be moving just before it strikes the ground?
a. 35 m/s b. 39 m/s c. 31 m/s d. 43 m/s
e. 54 m/s
13. A rifle is aimed horizontally at the center of a large target 60 m away. The initial speed of the bullet is 240 m/s. What is the distance from the center of the target to the point where the bullet strikes the target?
a. 48 cm b. 17 cm c. 31 cm d. 69 cm
e. 52 cm
14. A rock is thrown from the edge of the top of a 100-ft tall building at some unknown angle above the horizontal. The rock strikes the ground a horizontal distance of 160 ft from the base of the building 5.0 s after being thrown. Assume that the ground is level and that the side of the building is vertical. Determine the speed with which the rock was thrown.
a. 72 ft/s b. 77 ft/s c. 68 ft/s d. 82 ft/s
e. 87 ft/s
15. An airplane flies horizontally with a speed of 300 m/s at an altitude of 400 m. Assume that the ground is level. At what horizontal distance from a target must the pilot release a bomb so as to hit the target?
a. 3.0 km b. 2.4 km c. 3.3 km d. 2.7 km
e. 1.7 km
16. An object moving at a constant speed requires 6.0 s to go once around a circle with a diameter of 4.0 m. What is the magnitude of the instantaneous acceleration of the particle during this time?
a. 2.2 m/s2 b. 2.7 m/s2 c. 3.3 m/s2 d. 3.8 m/s2
e. 4.4 m/s2
17. A particle moves at a constant speed in a circular path with a radius of 2.06 cm. If the particle makes four revolutions each second, what is the magnitude of its acceleration?
a. 20 m/s2 b. 18 m/s2 c. 13 m/s2 d. 15 m/s2
e. 24 m/s2
18. A race car moving with a constant speed of 60 m/s completes one lap around a circular track in 50 s. What is the magnitude of the acceleration of the race car?
a. 8.8 m/s2 b. 7.5 m/s2 c. 9.4 m/s2 d. 6.3 m/s2
e. 5.3 m/s2
19. At the lowest point in a vertical dive (radius = 0.58 km), an airplane has a speed of 300 km/h which is not changing. Determine the magnitude of the acceleration of the pilot at this lowest point.
a. 26 m/s2 b. 21 m/s2 c. 16 m/s2 d. 12 m/s2
e. 8.8 m/s2
20. A carnival Ferris wheel has a 15-m radius and completes five turns about its horizontal axis every minute. What is the acceleration of a passenger at his lowest point during the ride?
a. 5.7 m/s2 downward b. 4.1 m/s2 upward c. 14 m/s2 downward
d. 4.1 m/s2 downward e. 19 m/s2 downward
21. A space station of diameter 80 m is turning about its axis at a constant rate. If the acceleration of the outer rim of the station is 2.5 m/s2, what is the period of revolution of the space station?
a. 22 s b. 19 s c. 25 s d. 28 s
e. 40 s
22. A car travels counterclockwise around a flat circle of radius 0.25 km at a constant speed of 20 m/s. When the car is at point A as shown in the figure, what is the car’s acceleration?
a. 1.6 m/s2, east b. Zero c. 1.6 m/s2, east d. 1.6 m/s2, north
e. 1.6 m/s2, west
23. A particle moves along a circular path having a radius of 2.0 m. At an instant when the speed of the particle is equal to 3.0 m/s and changing at the rate of 5.0 m/s2, what is the magnitude of the total acceleration of the particle?
a. 7.5 m/s2 b. 6.0 m/s2 c. 5.4 m/s2 d. 6.7 m/s2
e. 4.5 m/s2
24. A car travels in a flat circle of radius R. At a certain instant the velocity of the car is 20 m/s north, and the total acceleration of the car is 2.5 m/s2 37° south of west. Which of the following is correct?
a. R = 0.40 km, and the car’s speed is decreasing.
b. R = 0.20 km, and the car’s speed is decreasing.
c. R = 0.20 km, and the car’s speed is increasing.
d. R = 0.16 km, and the car’s speed is increasing.
e. R = 0.16 km, and the car’s speed is decreasing.
25. A car travels in a flat circle of radius R. At a certain instant the velocity of the car is 24 m/s west, and the total acceleration of the car is 2.5 m/s2 53° north of west. Which of the following is correct?
a. R = 0.29 km, and the car’s speed is increasing.
b. R = 0.23 km, and the car’s speed is decreasing.
c. R = 0.23 km, and the car’s speed is increasing.
d. R = 0.29 km, and the car’s speed is decreasing
e. R = 0.29 km, and the car’s speed is constant.
26. A stunt pilot performs a circular dive of radius 800 m. At the bottom of the dive (point B in the figure) the pilot has a speed of 200 m/s which at that instant is increasing at a rate of 20 m/s2. What acceleration does the pilot have at point B?
a. (50i + 20j) m/s2 b. (20i – 50j) m/s2 c. (20i + 50j) m/s2
d. (–20i + 50j) m/s2 e. (–50i + 20j) m/s2
27. The speed of a particle moving in a circle 2.0 m in radius increases at the constant rate of 4.4 m/s2. At an instant when the magnitude of the total acceleration is 6.0 m/s2, what is the speed of the particle?
a. 3.9 m/s b. 2.9 m/s c. 3.5 m/s d. 3.0 m/s
e. 1.4 m/s
28. A car travels in a flat circle of radius R. At a certain instant the velocity of the car is 24 m/s west, and the acceleration of the car has components of 2.4 m/s2 east and 1.8 m/s2 south. What is the radius of the circle?
a. 0.24 km b. 0.19 km c. 0.32 km d. 0.14 km
e. 0.27 km
29. A particle moves in the xy plane in a circle centered on the origin. At a certain instant the velocity and acceleration of the particle are 6.0i m/s and (3.0i + 4.0j) m/s2. What are the x and y coordinates of the particle at this moment?
a. x = 0, y = –9.0 m b. x = 0, y = +7.2 m c. x = 0, y = +9.0 m d. x = 0, y = –7.2 m e. x = 6.0 m, y = –9.0 m
30. A particle moves in the xy plane in a circle centered on the origin. At a certain instant the velocity and acceleration of the particle are 4.0j m/s and . What are the x and y coordinates of the particle at this moment?
a. x = –4.4 m, y = 0 b. x = +5.3 m, y = 0 c. x = –5.3 m, y = 0
d. x = +4.4 m, y = 0 e. x = –1.8 m, y = 0
31. A 0.14-km wide river flows with a uniform speed of 4.0 m/s toward the east. It takes 20 s for a boat to cross the river to a point directly north of its departure point on the south bank. What is the speed of the boat relative to the water?
a. 5.7 m/s b. 8.5 m/s c. 8.1 m/s d. 7.0 m/s
e. 6.4 m/s
32. A 0.20-km wide river has a uniform flow speed of 4.0 m/s toward the east. It takes 20 s for a boat to cross the river to a point directly north of its departure point on the south bank. In what direction must the boat be pointed in order to accomplish this?
a. 23° west of north b. 20° west of north c. 24° west of north
d. 22° west of north e. 17° west of north
33. A 0.20-km wide river has a uniform flow speed of 3.0 m/s toward the east. A boat with a speed of 8.0 m/s relative to the water leaves the south bank and heads in such a way that it crosses to a point directly north of its departure point. How long does it take the boat to cross the river?
a. 29 s b. 23 s c. 25 s d. 27 s
e. 17 s
34. A river has a steady speed of 0.30 m/s. A student swims downstream a distance of 1.2 km and returns to the starting point. If the student swims with respect to the water at a constant speed and the downstream portion of the swim requires 20 minutes, how much time is required for the entire swim?
a. 50 minutes b. 80 minutes c. 90 minutes d. 70 minutes
e. 60 minutes
35. The pilot of an aircraft flies due north relative to the ground in a wind blowing 40 km/h toward the east. If his speed relative to the ground is 80 km/h, what is the speed of his airplane relative to the air?
a. 89 km/h b. 85 km/h c. 81 km/h d. 76 km/h
e. 72 km/h
36. A car travels in a due northerly direction at a speed of 55 km/h. The traces of rain on the side windows of the car make an angle of 60 degrees with respect to the horizontal. If the rain is falling vertically with respect to the earth, what is the speed of the rain with respect to the earth?
a. 48 km/h b. 95 km/h c. 58 km/h d. 32 km/h
e. 80 km/h
37. A car travels in an oval path as shown below. vA = 25 m/s, West, and vB = 20 m/s, North. The ratio of the magnitude of the centripetal acceleration at B to that at A, is:
a. 0.512 b. 0.64 c. 0.8 d. 1.25
e. 1.56
38. Two ****s standing side by side in a restaurant pull their beaters out of the dough at the same instant. A glob of dough flies off each beater. Each glob lands on the top of a tin the same horizontal distance away and at its initial height. However, one lands later than the other. The explanation is that they left the beaters at angles q1 and q2 such that:
a. q2 = –q1. b. q1 + q2 = . c. q1 + q2 = . d. q1 + q2 = p.
e. q1 – q2 = p.
ما شاء الله كل هذه مسائل ف الميكانيكا !!
ولكن لي وجهة نظر ..اعتذر ابتداءاَ عن طرحها كوني لست طرفا فيها !!
اعتقد ان افضل طريقة للحصول ع حل لمثل هذا الكم من المسائل هو
معرفة فكرة المسألة والقانون المستخدم لحلها وهذه ستكون مهمة اساتذتنا ف المنتدى
اما الحل والخطوات واخراج الناتج فمن الافضل -بالنسبة لكم- هو ان تكون مهمتكم انتم
وفيما اعتقد ان هذه افضل طريقة للحصول ع حل لمثل هذا الكم من المسائل والاستفادة منها !!
فمن الصعب ان تجد من يحل لك اكثر من 30 مسألة كاملة وبخطواتها حتى اظن انه لا يوجد مدرس او دكتور سيفعل هذا مع طلبته بل سيدلهم ع طريقة الحل مع شرح بعض الامثلة ثم يترك عليهم مهمة حل بقية الامثلة وهم بدورهم سيسألونه فيما وقف امامهم من مسائل ولم يحصلوا فيها ع حل !!
تقبلوا مروري
وبالتوفيق ان شاء الله
انا افضل هذه الطريقة ايضا لاني اريد توضيح الفكرة فقط
نتابع مسائل في الميكانيكا وهي علي قانون نيوتن الثالث
يحمل سائق شاحنه صندوقين متماثلين علي شاحنه واحد فوق الاخر
ولم يحدث انزلاق اثناء الحركه وضح بالرسم في شكلين منفصلين القوه
التي تاثر علي كل صندوق عندما تتحرك الشاحنه علي طريق افقيه مستقيمه
1-بسرعه ثابته
2-بعجله تزايديه
3-بعجله تناقصيه
واذا كانت كتله كل صندوق 250 كيلو جرام احسب
1-مقدار قوه الاحتكاك التي تؤثر علي الصندوق العلوي من الصندوق السفلي
2-مقدار قوه الاحتكاك علي الصندوق السفلي بفعل الشاحنه عندما تكون مسرعه
بعجله قدرها 1.5متر لكل ثانيه