Question

A car advertisement states that a certain car can selerate from rest to 20 m/s in 7 seconds. Find the car's average acceleration​

Answer 1

Given :-

• Acceleration = 20 m/s
• Time = 7 sec

To Find :-

Average acceleration

Solution :-

As we are already knowing that

`\sf Acceleration_(Avg)` = TA/T

TA = Total acceleration

T = Time

A = 20/7

A = 2.85 m/s²

Answer 2

2.86m/s²

Step-by-step explanation:

`\boxed{average \: acceleration = (change \: in \: velocity)/(time) }`

Car's average acceleration

`= (20 - 0)/(7) \\ = 2.86 \: m/ {s}^(2) \: (3 \: s.f.)`

The reason why the change in velocity over time is average acceleration is because we are finding the total difference in velocity and dividing it against the total duration. This means that the acceleration of the car can vary throughout the 7 seconds (may not be a constant acceleration) but on average, the car's acceleration 2.86m/s², to 3 significant figures.

Change in velocity

= v -v₀

= final velocity -initial velocity

Since the car is at rest at the beginning, the initial velocity (v₀) is 0m/s.