MEDIUM
JEE Main
IMPORTANT
Earn 100

 A block is sent up a frictionless ramp along which an x-axis extends upward. In the figure shown below gives the kinetic energy of the block as a function of position x; the scale of the figure's vertical axis is set by Ks=50.0 J. If the block's initial speed is 5.00 m s-1, what is the normal force on the block?

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Important Questions on Kinetic Energy and Work

HARD
JEE Main
IMPORTANT

A cord is used to vertically lower an initially stationary block of mass M at a constant downward acceleration of g4. When the block has fallen a distance d, find (a) the work done by the cord's force on the block, (b) the work done by the gravitational force on the block, (c) the kinetic energy of the block, and (d) the speed of the block.

MEDIUM
JEE Main
IMPORTANT
A cave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. The lift is performed in three stages, each requiring a vertical distance of 12.0 m (a) the initially stationary spelunker is accelerated to a speed of 5.00 m s-1; (b) he is then lifted at the constant speed of 5.00 m s-1; (c) finally he is decelerated to zero speed. How much work is done on the 85.0 kg rescue by the force lifting him during each stage?
MEDIUM
JEE Main
IMPORTANT

In the figure shown below a constant force Fa of magnitude 82.0 N is applied to a 3.00 kg shoe box at angle ϕ=53.0o, causing the box to move up a frictionless ramp at a constant speed. How much work is done on the box by Fa when the box has moved through the vertical distance h=0.150 m?

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EASY
JEE Main
IMPORTANT

In the figure shown below a horizontal force Fa of magnitude 23.0 N is applied to a 3.00 kg psychology book as the book slides a distance d=0.580 m up a frictionless ramp at angle θ=30.0° (a) During the displacement, what is the net work done on the book by Fa, the gravitational force on the book and the normal force on the book? (b) If the book has zero kinetic energy at the start of the displacement, what is its speed at the end of the displacement? 

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HARD
JEE Main
IMPORTANT

In the figure shown below a 0.250 kg block of cheese lies on the floor of a 900 kg elevator cab that is being pulled upward by a cable through distance d1=2.40 m and then through distance d2=10.5 m. (a) Through d1, if the normal force on the block from the floor has constant magnitude FN=3.00 N, how much work is done on the cab by the force from the cable? (b) Through d2, if the work done on the cab by the (constant) force from the cable is 92.61 kJ, what is the magnitude of FN?

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MEDIUM
JEE Main
IMPORTANT
A spring of spring constant 5.0×103 N m-1 is stretched initially by 5.0 cm from the unstretchèd position. What is the work required to stretch it further by another 5.0 cm?
HARD
JEE Main
IMPORTANT

A spring and block are in the arrangement as in the figure shown below. When the block is pulled out to x=+4.0 cm, we must apply a force of magnitude 360 N to hold it there. We pull the block to x=11 cm and then release it. How much work does the spring do on the block as the block moves from xi=+5.0 cm to (a) x=+3.0 cm, (b) x=-3.0 cm, (c) x=-5.0 cm, and (d) x=-9.0 cm?

 

EASY
JEE Main
IMPORTANT
During spring semester at MIT, residents of the parallel buildings of the East Campus dorms battle one another with large catapults that are made with surgical hose mounted on a window frame. A balloon filled with dyed water is placed in a pouch attached to the hose, which is then stretched through the width of the room. Assume that the stretching of the hose obeys Hooke's law with a spring constant of 110 N m-1. If the hose is stretched by 5.00 m and then released, how much work does the force from the hose do on the balloon in the pouch by the time the hose reaches its relaxed length?