Given, mass of the dumb-bell (m) = 10 kg
Distance covered (s) = 80 cm = 0.8 m
Initial velocity (u) = 0 (it is dropped from a position of rest)
Acceleration (a) = 10ms-2
Terminal velocity (v) =?
Momentum of the dumb-bell when it hits the ground = mv
As per the third motion equation, v2 - u2 = 2as
Therefore, v2 - 0 = 2(10ms-1)(0.8 m) = 16m2s-2
v = 4 m/s
The momentum transferred by the dumb-bell to the floor = (10 kg) × (4 m/s) = 40 kg.m.s-1Answered by Shivani Kumari | 1 year ago
A motorcar of mass 1200 kg is moving along a straight line with a uniform velocity of 90 km/h. Its velocity is slowed down to 18 km/h in 4 s by an unbalanced external force. Calculate the acceleration and change in momentum. Also calculate the magnitude of the force required
Two persons manage to push a motorcar of mass 1200 kg at a uniform velocity along a level road. The same motorcar can be pushed by three persons to produce an acceleration of 0.2 m s-2. With what force does each person push the motorcar? (Assume that all persons push the motorcar with the same muscular effort)
The following is the distance-time table of an object in motion:
|Time (seconds)||Distance (meters)|
(a) What conclusion can you draw about the acceleration? Is it constant, increasing, decreasing, or zero?
(b) What do you infer about the forces acting on the object?
Akhtar, Kiran, and Rahul were riding in a motorcar that was moving with a high velocity on an expressway when an insect hit the windshield and got stuck on the windscreen. Akhtar and Kiran started pondering over the situation. Kiran suggested that the insect suffered a greater change in momentum as compared to the change in momentum of the motorcar (because the change in the velocity of the insect was much more than that of the motorcar). Akhtar said that since the motorcar was moving with a larger velocity, it exerted a larger force on the insect. And as a result the insect died. Rahul while putting an entirely new explanation said that both the motorcar and the insect experienced the same force and a change in their momentum. Comment on these suggestions.