A Car Accelerates Uniformly to Reach a Speed of 21 m/s

A car starts from rest and accelerates uniformly to reach a speed of 21m/s in 7.0 seconds

To find the acceleration of the object, we can use the formula:

A = (V - U) / t

Where:

A = acceleration

V = final velocity (21 m/s)

U = initial velocity (0 m/s since the car starts from rest)

t = time taken (7.0 seconds)

Plugging in the values:

A = (21 - 0) / 7

A = 21 / 7

A = 3 m/s^2

Therefore, the acceleration of the object is 3 m/s^2.

Working

It is given that:

Initial speed of the object, u = 0

Final speed of the object, v = 21 m/s

Time taken, t = 7 s

Using the equation of kinematics:

v = u + a × t

v = a × t

a = v / t

Substitute the values:

a = 21 m/s / 7 s

a = 3 m/s^2

So, the acceleration of the object is 3 m/s^2. This is the solution to the problem.