few physics questions...?

Question

True or Rewrite the in parentheses part to make it true.
11.The speed of a rotating object changes only if (torque) is applied to it.
12.The quantity of angular motion that is used with rotating objects is called (linear) momentum.
13.When a (torque) acts on an object, its angular momentum changes.
16.The torque on the planets orbiting the sun is zero because the gravitational force is directed toward the sun and, therefore, is not (perpendicular) to its velocity.
19.When a machine alters mechanical energy, the product of the force and distance is (zero).

Multiple Choice
21.If a net torque is applied to an object, that object will experience which of the following? a. a constant angular speed, b. an angular acceleration, c. a constant moment of inertia, d. an increasing moment of inertia
22.Which of the following quantities measures the ability of a force to rotate or accelerate an object around an axis? a. axis of rotation, b. lever arm, c. moment arm, d. torque

-Thanks

Answer 1

11 true; 12 angular; 13 true; 16 parallel; 19 nonzero; 21 b; 22 d.
You're welcome, but you really should study enough to understand the ideas of rotation, translation and energy. If they don't matter now, they may be quite important later.

Answer 2

ans) a million air bcoz truly,x-rays are so lively that they actual penetrate the exterior because the mild penetrates air.Infact mild won't be able to go by brick or metallic. 2.The wave will bypass swifter, increasing its %. bcoz,hence,mild is passing from denser to rarer medium via which its wavelengh alterations ,so its speed also(will advance).therefore everytime frequency is analogous. in view that frequency doesn't substitute,ability also continues to be a similar.there is not any lack of ability.!