Question

A van traveling down a slope with a uniform acceleration of 2.15 meters/second2 attains a speed of 20.00 meters/second after 7.00 seconds. What is the initial velocity of the van?
a. 0.00 meters/second
b. 3.65 meters/second
c. 4.95 meters/second
d. 35.05 meters/second
e. 120.75 meters/second

Answer 1

Answer: The correct answer is option(c).

Explanation:

Acceleration of the van ,a= $2.15 m/s^2$

Final velocity of the van,v = 20.00 m/s

Initial Velocity ,u= ?

Time taken by van to attain the velocity,t = 7 seconds

by using the firat equation of motion:

v = u + at

$20.00 m/s=u+2.15m/s^2\times 7 s$

$u=20.00m/s-2.15m/s^2\times 7 s=4.95 m/s$

The correct answer from the given option is 4.95m/s that is option (c).

Answer 2

Final velocity = initial velocity + (acceleration*time)
That is v = u + at
So 20 = u + (2.15*7)
20 = u + 15.05
Thus, u = 20 - 15.05
= 4.95 meters/second
that is C