Question

Two friends are each driving a car down Highway 101. During a particular 10 s interval, Jodi's car moves at a constant 60 mph. During that same time interval, Julie's car transitions from a speed of 20 mph to a speed of 30 mph. Whose car has the greater acceleration?

Answer 1

Answer:

Julie's car.

Explanation:

The acceleration of an object is equal to the rate of change of velocity. It can be given by :

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

Jodi's car moves at a constant 60 mph for 10 s.

Julie's car transitions from a speed of 20 mph to a speed of 30 mph for the same time interval i.e. 10 s.

For Jodi's car, the change in velocity is equal to 0. As a result, its acceleration is equal to 0 m/s².

For Julie's car,

Initial speed, u = 20 mph = 8.9408 m/s

Final speed, v = 30 mph = 13.4112 m/s

Acceleration,

$a=\dfrac{13.4112-8.9408}{10}\\\\a=0.447\ m/s^2$

It is clear that Julie's car has the greater acceleration than the Jodi's car.