Question

A force of 6.0 N is applied horizontally to a 3.0 kg crate initially at rest on a horizontal frictionless surface. After the crate is pushed for 1.5 seconds, it has a velocity of 3.0 m/s. Does this support Newton's second law of motion, that force equals mass times acceleration? Explain. 
a. Yes, because the acceleration of the crate is 2.0 m/s².

b. No, because the acceleration of the crate is 2.0 m/s².

c. Yes, because the mass and the velocity of the crate are equal.

d. No, because the mass and the velocity of the crate are equal. ​

Answer 1

Answer:

a. Yes, because the acceleration of the crate is 2.0 m/s².

Explanation:

Given

$Force = 6N$ --- f

$Mass = 3kg$ --- m

$Time = 1.5s$ --- t

$Velocity = 3.0m/s$ --- v

Required

Does the system support $F=ma$

Yes, it does and this is shown below

The crate is initially at rest; so:

$u = 0$

Using the first equation of motion

$v = u + at$

Substitute values for v, u and t

$3 = 0 + a*1.5$

$3 = 1.5a$

Make a the subject

$a = 3/1.5$

$a = 2$

Using $F = ma$

Substitute values for F and m

$6 = 3 * a$

Divide both sides by 3

$6/3 = 3/3 * a$

$2 = a$

$a = 2$

In both cases:

$a = 2$

Hence, option (a) is correct.