Question

14. Two masses are connected by a string which passes over a pulley with negligible mass and friction. One mass hangs vertically and one mass slides on a frictionless 30.0 degree incline. The vertically hanging mass is 6.00 kg and the mass on the incline is 4.00 kg. The magnitude of the acceleration of the 4.00 kg mass is 15. Two masses are connected by a string which passes over a pulley with negligible mass and friction. One mass hangs vertically and one mass slides on a frictionless horizontal surface. The vertically hanging mass is 6.00 kg and the mass on the horizontal surface is 4.00 kg. The acceleration of the 4.00 kg mass is 16. A sprinter runs 100.0 m in 9.87 seconds. If he travels at constant acceleration for the first 75.0 m and then at constant velocity for the final 25.0 m, what was his peak speed? 17. A mouse is running away from a cat at a speed of 0.75 m/s. At a distance of 1.25 m from his mouse hole, the mouse accelerates at a constant rate of 0.25 m/s2 until he reaches his hole safely. How long did it take the mouse to cover the last 1.25 m? 18. An object starts from rest with an acceleration of 2.0 m/s2 in the +x-direction for 3.0 seconds. It then reduces its acceleration to 1.0 m/s2 for 5.0 additional seconds. The total distance covered is about 19. A ball is thrown straight up with an initial speed of 30 m/s. a) What is its speed after 4.2 s? b) What is the maximum height reached by the ball? 20. Ball A is dropped from the top of a building. One second later ball B is dropped from the same point. As time progresses, the distance between them A) increases. B) decreases. C) remains constant. D) need more information 21. A ball is thrown straight up, reaches a maximum height, then falls to its initial height. As the ball is going up A) both its velocity and its acceleration point downward. B) its velocity points downward and its acceleration points upward. C) its velocity points upward and its acceleration points downward. D) both its velocity and its acceleration point upward.

Answer 1

here,

14)

the mass of hanging block , m1 = 6 kg

m2 = 4 kg

theta = 30 degree

the magnitude of the acceleration of the 4 kg mass , a = net force /effective mass

a = (m1 * g - m2 * g * sin(theta)) /(m1 + m2)

a = ( 6 * 9.81 - 4 * 9.81 * sin(30)) /(6 + 4)

a = 3.92 m/s^2

the magnitude of acceleration of 4 kg mass is 3.92 m/s^2