Physics Test 16...

A particle of mass m begins to slide down a fixed smooth sphere from the top as shown. What is its acceleration when it breaks off the sphere?

An automobile enters a turn of radius R. If the road is banked at an angle of 450 and the coefficient of friction is 1, the minimum and maximum speed with which the automobile can negotiate the turn without skidding is :

Figure shows the roller coaster track. Each car will start from rest at point A and will roll with negligible friction. It is important that there should be at least some small positive normal force exerted by the track on the car at all points, otherwise the car would leave the track. With the above fact, the minimum safe value for the radius of curvature at point B is (g = 10 m/s²) :

Two masses m₁ and m₂ which are connected with a light string, are placed over a frictionless pulley. This set up is placed over a weighing machine, as shown. Three combination of masses m₁ and m₂ are used, in first  case m₁ = 6 kg and m₂ = 2 kg, in second case m₁ = 5 kg and m₂ = 3kg and in third case m₁ = 4 kg and m₂ = 4 kg.  Masses are held stationary initially and then released. If the readings of the weighing machine after the release in three cases are W₁, W₂ and W3 respectively then :

The ratio of work done by the internal forces of a car in order to change its speed from 0 to V and  from V to 2V is (Assume that the car moves on a horizontal road) -

A weightless rod of length 2l carries two equal masses 'm', one tied at lower end A and  the other at the middle of the rod at B. The rod can rotate in vertical plane about a fixed horizontal axis passing through C. The rod is released from rest in horizontal position. The speed of the mass B at the instant rod, become vertical is :

Power versus time graph for a given force is given below. Work done by the force upto time t( < t₀).

A motor car is going due north at a speed of 50 km/h. It makes a 90º left turn without changing the speed. The change in the velocity of the car is about

A body is thrown horizontally with a velocity  from the top of a tower of height h. It strikes the level ground through the foot of the tower at a distance x from the tower. The value of x is

A train is standing on a platform , a man inside a compartment of a train drops a stone . At the same instant train starts to move with constant acceleration . The path of the particle as seen by the person who drops the stone is :