A body projected vertically from the earth reaches a height equal to earth’s radius before returning to the earth. The power exerted by the gravitational force: |
is greatest at the instant just before the body hits the earth.
remains constant throughout.
is greatest at the instant just after the body is projected.
is greatest at the highest position of the body.
A vertical spring with a force constant k is fixed on a table. A ball of mass m at a height h above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance d. The net work done in the process is: |
mg(h+d)+12kd2
mg(h+d)-12kd2
mg(h-d)-12kd2
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