1.A one kg mass suspended by a thread is first lifted up with an acceleration g / 2 and then lowered downward with an acceleration g / 2. The ratio of the tensions in the first and second case is

2.A 4 kg block is placed on a rough floor. The coefficient of static friction is 0.8. If a force of 19 N is applied on the block parallel to the floor, then the force of friction between the block and floor is

3.A ball hangs from a string inside a rail road car moving along a straight track. The string is observed to be inclined towards the rear of the car making a constant small angle with vertical. It shows that the car is

4.An isolated particle of mass m is moving in a horizontal plane (XY plane), along x-axis, at a certain height above the ground. It suddenly explodes into two fragments of masses m / 4 and 3m / 4. An instant later, the smaller fragment is at y = + 15 cm. The larger fragment at this instant is at y =

5.A rope of length L is pulled by a constant force F. What is the tension in the rope at a distance x from the end where the force is applied ?