Define 1 newton force. A balloon with mass 6 kg is descending down with an acceleration `5 ms^(-2)`. Calculate the mass of its contents that must be removed so that it starts moving up with the same acceleration.

rocket with a lift-off mass 20,000 kg is blasted, upwards with an initial acceleration of 5.0 m s~2. Calculate the initial thrust (force) of the blast.

A disc of mass 5 kg radius 0.5 m rolls on the ground at the rate of 10 ms^(-1) . Calculate its KE.

Find the force needed to produce an acceleration of 6 m/s2 in a ball of mass 4kg.

Certain force acting on a 20 kg mass changes its velocity from 5 m s^-1 to 2m s^-1 . Calculate the work done by the force.

If a force of 30 Newton is applied on a body of mass 15 kg. What will be its acceleration?

Figure 5.18 shows a man standing stationary with respect to a horizontal conveyor belt that is accelerating with 1 m s^2 . What is the net force on the man? If the coefficient of static friction between the man’s shoes and the belt is 0.2, up to what acceleration of the belt can the man continue to be stationary relative to the belt? (Mass of the man = 65 kg.)

Find the force required to move a train of mass 5000 quintals up an incline of 1 in 50 with an acceleration 2ms^-2 . Take force of friciton = .2N/s qunital and g = 10ms^-2 .

A planet reduces its radius by 1% with its mass remaining same. How acceleration due to gravity varies.

A body of mass 2kg is lying on a rough inclined plane of inclination 30^@ . Find the magnitude of the force needed to make the block move down the incline.

A man of mass 70 kg stands on a weighing scale in a lift which is moving (a) upwards with a uniform speed of 10 m s^1 (b) downwards with a uniform acceleration of 5 m s^2, upwards with a uniform acceleration of 5 m s-^1z. What would be the readings on the scale in each case? What would be the reading if the lift mechanism failed and it hurtled down freely under gravity?