Answer:
My answer is when the ball is going it experience kinetic energy which is the energy of a moving object while when the ball has stopped then it will have potential energy which means it's at rest so for the ball not to experience friction then there is a gain in kinetic energy and decrease in potential energy.
Answer:
∵ 
Explanation:
The tangential acceleration of a cart moving at a constant speed in a circle is:
The angular velocity is constant when the circular speed is constant.
We know that the (instantaneous) tangential velocity of such object is given by:

Now for angular acceleration we have a constant angular speed:

And angular acceleration is related to tangential acceleration as:


Answer:
I think it's the most important part in this
When the spring is extended by 44.5 cm - 34.0 cm = 10.5 cm = 0.105 m, it exerts a restoring force with magnitude R such that the net force on the mass is
∑ F = R - mg = 0
where mg = weight of the mass = (7.00 kg) g = 68.6 N.
It follows that R = 68.6 N, and by Hooke's law, the spring constant is k such that
k (0.105 m) = 68.6 N ⇒ k = (68.6 N) / (0.105 m) ≈ 653 N/m