OAR OAR Mechanical Comprehension: Forces Questions and Answers 3

Question 1

A 1,200 kg car accelerates from rest at 3 m/s². What net force is required to produce this acceleration?

Accepted Answer

3,600 N

Answer

Using Newton's Second Law, F = ma = 1,200 × 3 = 3,600 N.

Question 2

Three coplanar forces of 5 N, 3 N, and 7 N all act to the right on an object. What is the resultant force?

Accepted Answer

15 N to the right

Answer

When forces act in the same direction, the resultant is their sum: 5 + 3 + 7 = 15 N to the right.

Question 3

A 20 kg crate requires 60 N of horizontal force to start sliding on a surface. What is the coefficient of static friction? (g = 10 m/s²)

Accepted Answer

0.3

Answer

μs = F / (mg) = 60 / (20 × 10) = 60 / 200 = 0.3.

Question 4

A 15 kg object is in free fall near Earth's surface. Ignoring air resistance, what is the net force on the object? (g = 9.8 m/s²)

Accepted Answer

147 N downward

Answer

The only force is gravity: F = mg = 15 × 9.8 = 147 N downward.

Question 5

Two ropes support a 100 N weight. If the ropes make equal angles and each rope carries an equal share, what is the vertical component of tension in each rope?

Accepted Answer

50 N

Answer

Since the system is in equilibrium and the ropes share equally, each rope's vertical tension component is 100 / 2 = 50 N.

OAR Test Practice Test

OAR Test Practice Test

OAR OAR Mechanical Comprehension: Forces Questions and Answers 3