Related InterviewSolutions

• According to the third law of motion, when we push on an object, the object pushes back on us with an equal and opposite force. If the object is a massive truck parked along the roadside, it will probably not move. A student justifies this by answering that the two opposite and equal forces cancel each other. Comment on this logic and explain why the truck does not move.
• From a rifle of mass `4kg`, a bullet of mass `50g` is fired with an initial velocity of `35m//s`. Calculate the initial recoil velocity of the rifle.
• A motorcar of mass `1200kg` is moving along a straight line with a uniform velocity of `90 km//h`. Its velocity is slowed down to `18 km//h` in `4s` by an unbalanced external force. Calculate the acceleration and change in momentum. Also, calculate the magnitude of the force required.
• The velocity time graph of a ball of mass `20g` moving along a straight line on a long table is given in (figure) How much force does the table exert on the ball to bring it to rest?
• Two object, each of mass `1.5 kg`, are moving in the same straight line but in opposite directions, The velocity of each object is `2.5 ms^(-1)` before the collision during which they stick together. What will be the velocity of the combined object after collision?
• How much momentum will a dumb-bell of mass `10kg` transfer to the floor if it falls a height of `80 cm`? Take its downward acceleration to be `10 m//s^(2)`.
• A force of `5N` gives a mass `m_(1)`, an acceleration of `10m//s^(2)`, and a mass `m_(2)`, an acceleration of `20m//s^(2)`. What acceleration would it give if both the masses were tied together?
• An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non-zero velocity? If yes, state the conditions that must be placed on the magnitude and direction of the velocity. If no, provide a reason.
• Why is it advised to tie any luggage kept on the roof of a bus with a rope?
• A stone of `1kg` is thrown with a velocity of `20 ms^(-1)` across the frozen surface of lake and comes to rest after travelling a distance of `50m`. What is the force of friction between the stone and the ice?