Answer:
D. a person pulling a sled.
Explanation:
contact force only occurs when something directly comes in contact with another object.
a. is wrong because that is called magnetic force.
b. gravitational force
c. is an electrical force
The ant would drag the sugar 500m
Good luck!
Answer: True.
Explanation:
A resistance force is also known as friction. And the efficiency of a machine is affected by friction.
A machine of lower efficiency has higher magnitude of friction than a machine of higher efficiency.
Therefore, To obtain the same resistance force, a greater force must be exerted in a machine of lower efficiency than in a machine of higher efficiency. This is true
Answer:
The Sun-Earth-Moon system happens to exhibit a striking geometric coincidence, which we examine in the first problem. PROBLEM 1. To an observer on Earth, the Sun and the Moon subtend almost the same angle in the sky. The average angle is 0.52 degrees for the Moon and 0.53 degrees for the Sun.