Answer:
D. Friction
Explanation:
Friction is a force that opposes motion. So a perpetual motion machine can never be built because it is impossible to eliminate frictional force. It can only be reduced
Answer:
Kinetic energy
Explanation:
Kinetic energy is a function of velocity. Since the rider is moving at a certain speed, he's demonstrating kinetic energy. It can't be potential energy because potential energy encompass mgh
Answer:
During <u>winter (late December/early January)</u> the Earth is closest to the Sun and during <u>summer (late June/early July)</u> the Earth is farthest from the Sun.
Explanation:
In the northern hemisphere, the earth usually comes closer to the sun during the time of winter season, mostly in late December or early January.
On the other hand, the earth is farthest from the sun during the time of summer season, mostly in late June or early July.
When the earth is closer to the sun, during the winter, it is comparatively cold. It is due to the absorption of a lesser amount of incoming solar radiation. The tilt of the earth is also responsible for this low temperature.
But, when the earth is farthest from the sun, during the summer, it is comparatively hot. It is due to the absorption of a large amount of incoming solar radiation.
The amplitude of a wave tells us about the intensity or brightness of the light relative to other light waves of the same wavelength.
