Answer:
a) 70 N, b) b. Each initially applied a force bigger than static friction to get the box moving and accelerating, then when the desired final speed was achieved they reduced the force to make the net force zero.
Explanation:
a) A constant speed means that magnitude of friction force is equal to the magnitude of the external force. The friction force is directly proportional to the normal force, which is equal to the weight of the box. Therefore, the magnitude of the force is 70 N.
b) Alice used initially a greater force to accelerate the box up to needed speed and later reduced the external force to keep speed constant. The right choice is option b.
The coriolis effect is due to the rotation of the earth. Look up youtube videos on it, its pretty cool. If we didn't have coriolis effect then hurricane's wouldn't even form! Also it affects the trajectory of hurricanes. If you look at a path a hurricane takes it always curves quite a bit. That's also because of the coriolis affect. Imagine you're on a merry go round or on some spinning disk. You throw a ball towards the center. The ball will seem to curve away from your target because you're spinning. Now its not because the ball curved and you missed, the ball goes in a straight line but because of the spinning the target you aimed at shifted.
<em>mass (m)= 5 kg</em>
<em>height (h)= 9m </em>
<em>gravity (g)= 9.8 m/s^2</em>
It has Potential energy. (PE)
• PE = mgh
Replacing:
PE = 5 * 9.8 * 9 = 441 Joules
Wind is caused by differences in the atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the lower pressure area, resulting in winds of various speeds. On a rotating planet, air will also be deflected by the Coriolis effect, except exactly on the equator.
