Will somebody please help mw with these Physics questions.

Question

A ball attached to a string is whirled in a circle. If the string breaks, what causes the ball to move in a straight line?

a. inertia

b. centripetal force

c. centripetal acceleration

d. centrifugal force

A boy can raise a rock that weighs 120 N by using a lever and applying a force of 25 N. What is the mechanical advantage of the lever?

a. 4.8

b. 225

c. .21

d. 3.5

A dog sits 1.25 m from the center of a merry go round and revolves at a tangential speed of 2.0 m/s. If the dog's mass is 19.3 kg, what is the magnitude of the centripetal force on the dog?

a. 40. N

b. 61.8 N

c. 103 N

d. 21.3 N

Answer 1

#1 inertia Newton's first law.

#2 4.8 output force / input force

#3 61.8 N 2² / 1.25 x 19.3 = 61.8

Answer 2

1) look up the definition of each of your possible answers. this should help you to narrow the answer. Think about Newton's 1st law also

2) Mechanical advantage is the term used to describe how much a machine/tool amplifies an applied force. [applied force] X [mechanical advantage] = [output force] The output force in this question is the 120 N required to lift the rock and the 25N is the applied force.

3) Newton's 2nd Law: F = ma For circular motion, the acceleration is related to the distance from the center of rotation and the tangential velocity: a = v/r²