Question

What was the initial speed of a car if its speed is 40 m/s after 5 seconds of accelerating at 4 m/s2?

A. 20 m/s
B. 10 m/s
C. 25 m/s
D. 60 m/s

Answer 1

[A] 20 m/s

Step-by-step explanation:

Given:

Time (t)= 5 seconds

Acceleration (a)= 4 m/s²

We know v=u+at

• V- final velocity
• U- initial velocity
• A- acceleration
• T- time

Speed = Velocity {in this question}

⇒ 40m/s=u+4×5 m/s

⇒ 40m/s=u+20 m/s

⇒ u=(40−20) m/s

u =20m/s

Hence, the initial speed of a car if its speed is 40 m/s after 5 seconds of accelerating at 4 m/s² is 20 m/s.

RevyBreeze

Answer 2

40 m/s ·

Step-by-step explanation:

t= 5 s · a= 4 m/s².

we use the formula:V= u + atV