8. An animal is walking forward. There is an applied force from the animal of 25 N to the right, a frictional force of 18 N to the left, a force of gravity of 65 N down and the animal is being pushed up by the ground with 65 N. What best describes the motion of the animal?

Question

a
The animal will move to the left due to an unbalanced force on the left
b
The animal will move to the right due to an unbalanced force on the right
c
The animal will move down due to an unbalanced force down
d
The animal will move up due to an unbalanced force upwards

10. Why is it generally easier to push a heavy object that is already moving instead of the same heavy object that is stationary

a
The force of gravity on the object is different if it is stationary or not.
b
The force of friction on the object is different if it is stationary or not
c
The force of the push on the object is different if it is stationary or not
d
The normal force on the object is different if it is stationary or not

11. Which of the followng is Newton's Second Law?

a
An object in motion will stay in motion unless acted upon by an unbalanced outside force
b
Force = mass times acceleration
c
When one object puts a force on the another object, the second object puts a force back on the first, equal in magnitude and opposite in direction

12. What are the primary forces that act upon a baseball and a bat during their collision with each other?
a
The force of ball on bat and the force of gravity on ball
b
The force of gravity on the bat and the force of friction on the ball
c
The normal force of the ball and the force of friction on the bat
d
The force of ball on bat and the force of the bat on ball

13. Two rockets are being tested. Both rockets have the same mass. One rocket accelerates at a higher rate than another rocket. What could be true about the difference between the rockets?

a
One rocket has more fuel than the other
b
One rocket is more streamlined than the other
c
One rocket engine produces more force than the other
d
One rocket is more badly designed than the other

Answer 1

Here are the answers to your questions:

8. The best description of the motion of the animal:

• b The animal will move to the right due to an unbalanced force on the right.
  • Explanation: There is a net force of 25 N (to the right) - 18 N (to the left) = 7 N to the right, which will cause the animal to move to the right.

10. Why is it generally easier to push a heavy object that is already moving instead of the same heavy object that is stationary:

• b The force of friction on the object is different if it is stationary or not.
  • Explanation: The static friction (friction on stationary objects) is typically greater than the kinetic friction (friction on moving objects), which is why it is easier to push an object that is already in motion.

11. Which of the following is Newton's Second Law?

• b Force = mass times acceleration.
  • Explanation: Newton's Second Law is described by the equation \( F = ma \), where F is the net force acting on an object, m is the mass of the object, and a is its acceleration.

12. The primary forces that act upon a baseball and a bat during their collision with each other:

• d The force of ball on bat and the force of the bat on ball.
  • Explanation: According to Newton's Third Law, for every action, there is an equal and opposite reaction. When the ball collides with the bat, the ball exerts a force on the bat, and the bat exerts an equal and opposite force on the ball.

13. What could be true about the difference between the rockets?

• c One rocket engine produces more force than the other.
  • Explanation: The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass (Newton's Second Law). Therefore, if two rockets have the same mass but different accelerations, the one that accelerates more must produce more force.