Give one word/term for the following descriptions.
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The force with which the Earth attracts a body.
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The unit for energy.
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The movement of a body in the Earth's gravitational field
when no other forces act on it.
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The sum of the potential and kinetic energy of a body.
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The amount of matter an object is made up of.
Solution not yet available
Consider the situation where an apple falls from a tree. Indicate whether the
following statements regarding this situation are TRUE or FALSE. Write
only “true” or “false”. If the statement is
false, write down the correct statement.
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The potential energy of the apple is a maximum when the apple
lands on the ground.
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The kinetic energy remains constant throughout the motion.
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To calculate the potential energy of the apple we need the
mass of the apple and the height of the tree.
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The mechanical energy is a maximum only at the beginning of
the motion.
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The apple falls at an acceleration of \(\text{9,8}\)
\(\text{m·s$^{-2}$}\) .
Solution not yet available
A man fires a rock out of a slingshot directly upward. The rock has an
initial velocity of \(\text{15}\) \(\text{m·s$^{-1}$}\) .
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What is the maximum height that the rock will reach?
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Draw graphs to show how the potential energy, kinetic energy
and mechanical energy of the rock changes as it moves to
its highest point.
Solution not yet available
A metal ball of mass \(\text{200}\) \(\text{g}\) is tied to a light string to
make a pendulum. The ball is pulled to the side to a height (A),
\(\text{10}\) \(\text{cm}\) above the lowest point of the swing (B). Air
friction and the mass of the string can be ignored. The ball is let go
to swing freely.
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Calculate the potential energy of the ball at point A.
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Calculate the kinetic energy of the ball at point B.
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What is the maximum velocity that the ball will reach during
its motion?
Solution not yet available
A truck of mass \(\text{12}\) \(\text{tons}\) is parked at the top of a hill,
\(\text{150}\) \(\text{m}\) high. The truck driver lets the truck run
freely down the hill to the bottom.
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What is the maximum velocity that the truck can achieve at
the bottom of the hill?
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Will the truck achieve this velocity? Why/why not?
Solution not yet available
A stone is dropped from a window, \(\text{6}\) \(\text{m}\) above the ground.
The mass of the stone is \(\text{25}\) \(\text{g}\).
Use the Principle of Conservation of Energy to determine the speed with
which the stone strikes the ground.
Solution not yet available
