Question

this diagram shows a ball rolling from left to right along a frictionless surface. in which sections will the ball be subjected to an unbalanced force?
section 1 section 2 section 3 section 4 section 5
a. sections 3 and 4
b. sections 2 and 5
c. sections 1, 3, and 4
d. sections 1 and 4

Explanation:

Step1: Understand Newton's first law

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. On a frictionless surface, if the ball's speed or direction changes, there is an unbalanced force.

Step2: Analyze each section

• Section 1: The ball is moving down a slope. Its speed is increasing (accelerating), so there is an unbalanced force (component of gravitational force along the slope).
• Section 2: The ball is on a horizontal surface. Since there is no friction and it's moving at a constant speed (assuming no other forces), there is no unbalanced force.
• Section 3: The ball is moving up a slope. Its speed is decreasing (decelerating), so there is an unbalanced force (component of gravitational force opposite to the motion).
• Section 4: The ball is moving down a slope. Its speed is increasing (accelerating), so there is an unbalanced force (component of gravitational force along the slope).
• Section 5: The ball is on a horizontal surface. Since there is no friction and it's moving at a constant speed (assuming no other forces), there is no unbalanced force.

Answer:

C. Sections 1, 3, and 4