I think is c because your seeing how your using you’re time.
4 km in 30 min then 8 km in 60min or an hr. so 8km/hr.
Answer:
a. an increase in the mass on the spring.
Explanation:
T = 2π/ω = 2π/√(k/m) = 2π√(m/k)
2π is a constant
as m is in the numerator, increasing mass will increase the period.
Answer:
(D) friction from the ground changes the ball's
kinetic energy into heat
Explanation:
When a ball is roll on the ground, the electrons in the atoms on the surface of the ground push against the electrons in the atoms on the surface of your ball that is touching the ground. A rolling ball stops because the surface on which it rolls resists its motion,that is when two surfaces come in contact with each other, the surface of one tends to oppose the motion of the other. A rolling ball stops because of friction.
