Question

A car starts from rest and accelerates along a straight line path in one minute. It finally attains a velocity of 40 meters/second. What is the car's average acceleration?
a. 1.5 meters/second^2
b. 1.5 meters/second
c. 0.66 meters/second^2
d. 0.66 meters/second

Answer 1

Answer: The correct answer is 0.66 meters/second^2.

Explanation:

The expression for the acceleration is as follows:

$a= \frac{v-u}{t}$

Here, a is the acceleration, v is the final velocity and u is the initial velocity.

It is given in the problem that A car starts from rest and accelerates along a straight line path in one minute. It finally attains a velocity of 40 meters/second.

The time taken by a car is time, t= 1 min = 60 s.

Calculate the car's average acceleration.

Put t= 60 s, u= 0 and v= 40 m/s in the above expression.

$a= \frac{40-0}{60}$

$a=0.66 meters/second^2$

Therefore, the correct option is (c).

Answer 2

The average acceleration of the car is given by:
$a= \frac{v_f-v_i}{t}$
where $v_i$ is the initial velocity of the car, $v_f$ is its final velocity and t is the time taken to attain the final speed. The car in the problem starts from rest, therefore its initial velocity is zero: $v_i=0$. The final velocity is $v_f=40 m/s$, while the time taken is
$t=1 min= 60 s$
Therefore, the average acceleration of the car is
$a= \frac{40}{60} =0.66 m/s^2$
and the correct answer is C.