What are the two ways to change the frictional force between two solid surfaces

After a rock that is thrown straight up reaches the top of its path and is starting to fall back down, its acceleration is (neglecting air resistance) A. less than when it was at the top of its path. B.

If a 1-kg object stretches a spring by 2 cm, then how much will the spring be stretched when it supports a 3-kg object? (Assume the spring does not reach its elastic limit.

If something is hot, does it contain heat or thermal energy? neither heat only thermal energy only either one because they are the same thing

Which choice defines AC and DC correctly? In AC, electrons moving in one direction. In DC, they move in one direction and then in the other direction. In DC, electrons move in only one direction.

Three eyewitnesses at the scene of a car accident were asked how long the accident lasted. They responded with 11 seconds, 12 seconds, and 11 seconds. The traffic camera recorded the accident and it actually lasted 7 seconds.

A Blu-ray disc is approximately 11 centimeters in diameter. The drive motor of a Blu-ray player is able to rotate up to 10,000 revolutions per minute. (a) Find the maximum angular speed (in radians per second) of a Blu-ray disc as it rotates

A body has translatory motion if it moves along a

What is Nothing. (sorry i have been wondering this for a very long time)

What is the weight of a 15kg dog on earth?

Identify the scenario below as to whether they increase, decrease, or not change the frequency in which a string vibrates and thus change its pitch. Assume that no other changes are happening. 1. Tightening a string for greater tension 2.