A boy puts a heavy box of mass M of his head and jumps down from the top of a multistoried building to the ground. How much is the force exerted by the box on hishead during his free fall? Does the for greatly increase during the period he balances himself after striking teh ground?

A man of mass 80kg pushes a box of mass 20kg horizontally. The man moves the box with a constant acceleration of 2m//s^(2) but his foot does not slip on the ground. There is no friciton between the box and the ground, whereas there is sufficient friction between the man's foot and the ground to prevent him from slipping. Assertion :- The force applied by the man on the box is equal and opposite to the force applied by the force applied by the box on the man. Reason :- Friction force applied by the ground on the man is 200N .

A man of mass 80kg pushes box of mass 20kg horizontaly. The man moves the box with a constant acceleration of 2 m//s^(2) but his foot does not slip on the ground. There is no friction between the box and the ground. There is no friction between the box and the ground. whereas there is sufficient friction between the man's foot and the ground to prevent him from slipping. Assertion:- The force applied by the man on the box is equal and opposite to the force applied by the force applid by the box on the man. Reason:- Friction force applied by the ground on the man is 200N.

small block of mass 200 g is kept at the top of a frictioinless incline which is 10 m long and 3.2 m high. How much work was required a. to lift the block from the ground nd put it at thetop b. to side the block up the incline? What will be the speed of the block when it reaches the ground if, c. it falls off the incline and drops vertically on the ground d. it slides down the incline? Take g=10 m/s^2 .

An inquistive student, determined to test the law of gravity for himself, walks to the top of a building og 145 floors, with every floor of height 4 m, having a stopwatch in his hand (the first floor is at a height of 4 m from the ground level). From there he jumps off with negligible speed and hence starts rolling freely. A rocketeer arrives at the scene 5 s later and dives off from the top of the building to save the student. The rocketeer leaves the roof with an initial downward speed v_0 . In order to catch the student at a sufficiently great height above ground so that the rocketeer and the student slow down and arrive at the ground with zero velocity. The upward acceleration that accomplishes this is provided by rocketeer's jet pack, which he turns on just as he catches the student, before the rocketeer is in free fall. To prevent any discomfort to the student, the magnitude of the acceleration of the rocketeer and the student as they move downward together should not exceed 5 g. The position - time graph for rocketeer would be (take the top of building as origin, and vertical downward direction as positive y-axis.)

An inquistive student, determined to test the law of gravity for himself, walks to the top of a building og 145 floors, with every floor of height 4 m, having a stopwatch in his hand (the first floor is at a height of 4 m from the ground level). From there he jumps off with negligible speed and hence starts rolling freely. A rocketeer arrives at the scene 5 s later and dives off from the top of the building to save the student. The rocketeer leaves the roof with an initial downward speed v_0 . In order to catch the student at a sufficiently great height above ground so that the rocketeer and the student slow down and arrive at the ground with zero velocity. The upward acceleration that accomplishes this is provided by rocketeer's jet pack, which he turns on just as he catches the student, before the rocketeer is in free fall. To prevent any discomfort to the student, the magnitude of the acceleration of the rocketeer and the student as they move downward together should not exceed 5 g. What should be the initial downward speed of the rocketeer so that he catches the student at the top of 100 the floor for safe landing ?

An inquistive student, determined to test the law of gravity for himself, walks to the top of a building og 145 floors, with every floor of height 4 m, having a stopwatch in his hand (the first floor is at a height of 4 m from the ground level). From there he jumps off with negligible speed and hence starts rolling freely. A rocketeer arrives at the scene 5 s later and dives off from the top of the building to save the student. The rocketeer leaves the roof with an initial downward speed v_0 . In order to catch the student at a sufficiently great height above ground so that the rocketeer and the student slow down and arrive at the ground with zero velocity. The upward acceleration that accomplishes this is provided by rocketeer's jet pack, which he turns on just as he catches the student, before the rocketeer is in free fall. To prevent any discomfort to the student, the magnitude of the acceleration of the rocketeer and the student as they move downward together should not exceed 5 g. In Q.1, what would be the approximate retardation to be given by jet pack along for safe landing?

An inquistive student, determined to test the law of gravity for himself, walks to the top of a building og 145 floors, with every floor of height 4 m, having a stopwatch in his hand (the first floor is at a height of 4 m from the ground level). From there he jumps off with negligible speed and hence starts rolling freely. A rocketeer arrives at the scene 5 s later and dives off from the top of the building to save the student. The rocketeer leaves the roof with an initial downward speed v_0 . In order to catch the student at a sufficiently great height above ground so that the rocketeer and the student slow down and arrive at the ground with zero velocity. The upward acceleration that accomplishes this is provided by rocketeer's jet pack, which he turns on just as he catches the student, before the rocketeer is in free fall. To prevent any discomfort to the student, the magnitude of the acceleration of the rocketeer and the student as they move downward together should not exceed 5 g. The correct velocity - time graph for the rocketeer would be

A box of mass M is at rest on a horizontal surface. A boy of mass m (lt M) wants to push the box by applying a horizontal force on it. The boy knows that he will not be able to push the box as the coefficient of friction mu between his shoes and ground is almost equal to that between the box and the ground. He decides to run, acquire a speed u and then bang into the box. After hitting the box, the boy keeps pushing as hard as possible. What is the maximum distance through which the box can be displaced this way ?

If a man of ,mass M jumps to the ground from a height h and his centre of mass noves a distance x in the time taken by him to 'hit' the ground the average force acting on him (assuming his retardation to be constant during his impact with the ground) is :

A 50 kg man is standing at the centre of a 30 kg platform A. Length of the platform is 10 m and coefficient of friction between the platform and the horizontal ground is 0.2. Man is holding one end of a light rope which is connected to a 50 kg box B. The coefficient of friction between the box and the ground is 0.5. The man pulls the rope so as to slowly move the box and ensuring that he himself does not move relative to the ground. If the shoes of the man does not slip on the platform, calculate how much time it will take for the man to fall off the platform. Assume that rope remains horizontal, and coefficient of friction between shoes and the platform is 0.6.