A refrigerator weighing 1500 N is to be lifted onto a truck bed that is 1.0 m ab

Question

A refrigerator weighing 1500 N is to be lifted onto a truck bed that is 1.0 m above the ground. When pushed up a ramp 2.0 m in length a force of only 700 N is required to move constant velocity. Comparing the work involved in lifting the refrigerator straight up to the work in pushing it along the ramp, there is less work required when the ramp is employed. more work required when the ramp is employed. an equal amount of work is required in each case. A ball at the end of a string is swinging as a simple pendulum. Assuming no loss in due to friction, we can say for the ball that the potential energy is maximum at each end of the motion. the mechanical energy changes and is maximum where the kinetic energy is minimum. the mechanical energy changes and is maximum where the kinetic energy is maximum. the kinetic energy does not change but the potential energy does. On a frictionless tabletop, a force is applied to an object the object's velocity is and the force is perpendicular to the tabletop. Which of the following is true? The applied force is friction. The total energy of the object does not change. There cannot be more than one force on the object. The force does work on the object Work is done on an object to increase its total energy. Which one of the following The total work done must be equal to the energy lost to heat and sound. Both the kinetic energy and potential energy can be larger. If the potential energy increases, then the kinetic energy must decrease. The object must have a larger speed and smaller height above the ground. If the kinetic energy of an object increase, then the potential energy must decrease. the total energy must increase. there can only be one force on the object. the speed must increase as well. If an object has a larger potential energy than kinetic energy, the speed of the object will increase. the speed of the object will not change. the speed of the object will decrease. It is not possible to predict what the speed will be; it depends on the situation

Explanation / Answer

( 5 )

While you lifting the refregirator, the work is done against gravity. When you push the refrigiratore, the work is done against friction. The friciton reduces the net work done. Hence it is greater than the work done as compared to work in pushing along the ramp.

Correct option is ( B )

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( 6 )

The mechanical energy is constant, whereas the kinetic energy is changing into potential energy vice versa. The potential energy is maximum at ends

Thus, the correct option is ( A )

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( 7 )

As the surface is frictionlesss, it is not a friction force. In this case, more than one force exist, applied force and gravity. As force is perpendicular, no work is done. The total energy of the system is constant.

Thus, the correct option is ( B )

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( 8 )

The mechanical energy is constant, whereas the kinetic energy is changing into potential energy vice versa

Correct option is ( C )

( 9)

The kinetic energy depends on mass and velocity. So, need not increse velocity only, mass also effcts. As per conservation of energy, the potential energy decreases as KE increases, and hence total energy constant

Correct option is ( A )

( 10 )

In this case, we can not judge the speed of object.

Correct option is ( D )

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