As the skateboard rolls down the ramp it loses potential energy and gains kinetic energy.
Answer:
C
Explanation:
If a pulley system has an efficiency of 74.2%, then only that fraction of the work performed will be useful. 74.2%=0.742. 0.742*200 is about 148J. Hope this helps!
Answer:
A
Explanation:
Constant speed (without change in direction) is not accelerating. If you are slowing down, speeding up, or changing direction, you are accelerating
Kepler derived his three laws of planetary motion entirely from
observations of the planets and their motions in the sky.
Newton published his law of universal gravitation almost a hundred
years later. Using some calculus and some analytic geometry, which
any serious sophomore in an engineering college should be able to do,
it can be shown that IF Newton's law of gravitation is correct, then it MUST
lead to Kepler's laws. Gravity, as Newton described it, must make the planets
in their orbits behave exactly as they do.
This demonstration is a tremendous boost for the work of both Kepler
and Newton.
