An object travels 7.5 m/s toward the west. Under the influence of a constant net force of 5.2 kN, after 4.3 s, it is travelling 2.5 m/s toward the east. What is its mass?
A) 2200 kg
B) 4500 kg
C) 6000 kg
D) 12000 kg

Question

Quizplus · Accepted Answer

First, we need to calculate the acceleration of the object using the formula:

a = (vf - vi) / t
where
a = acceleration
vf = final velocity = 2.5 m/s towards east (positive direction)
vi = initial velocity = 7.5 m/s towards west (negative direction)
t = time = 4.3 s

a = (2.5 - (-7.5)) / 4.3
a = 2.326 m/s^2 towards east

Then, we can use Newton's second law of motion to find the mass of the object:

Fnet = ma
where
Fnet = net force = 5.2 kN towards east (positive direction)
m = mass
a = acceleration = 2.326 m/s^2 towards east (positive direction)

5.2 kN = m x 2.326 m/s^2
m = 5.2 kN / 2.326 m/s^2
m = 2240 kg

Therefore, the mass of the object is approximately 2200 kg. The best choice is A.

An Object Travels 7