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?

Question Image 

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?

Question Image   

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? 

   Question Image  

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?

Question Image

HARD
JEE Main
IMPORTANT

As a 2.5 kg body moves in the positive direction along an x-axis, a single force acts on it. The force is given by Fx=-6x N, with x in meters. The velocity at x=3.5 m is 8.5 m s-1.

(a) Find the velocity of the body at x=4.5 m.

(b) Find the positive value of x at which the body has a velocity of 5.5 m s-1.

MEDIUM
JEE Main
IMPORTANT

The block in the figure shown below lies on a horizontal frictionless surface and the spring constant is 50 N m-1. Initially, the spring is at its relaxed length and the block is stationary at position x=0. Then an applied force with a constant magnitude of 3.0 N pulls the block in the positive direction of the x-axis, stretching the spring until the block stops. When that stopping point is reached, what are
(a) the position of the block, (b) the work that has been done on the block by the applied force and (c) the work that has been done on the block by the spring force? During the block's displacement, what are (d) the block's position when its kinetic energy is maximum and (e) the value of that maximum kinetic energy?

Question Image

EASY
JEE Main
IMPORTANT

A 15 kg brick moves along an x-axis. Its acceleration as a function of its position is shown in the figure shown below. The scale of the figure's vertical axis is set by as=24 m s-2. What is the net work performed on the brick by the force causing the acceleration as the brick moves from x=0 to x=8.0 m?

Question Image