Question

By what factor will the kinetic energy change if the speed of the baseball is decreased to 54.8 mi/h? Express your answer as an integer.

Answer 1

Answer:

The Kinetic Energy is approximately 3 times decreased

Explanation:

A baseball weighs 5.13 oz.  

a)What is the kinetic energy, in joules, of this baseball when it is thrown by a major league pitcher at 95.o mi/h?  

b) By what factor will the kinetic energy change if the speed of the baseball is decreased to 54.8 mi/h? Express your answer as an integer.

Kinetic Energy (KE)=0.5×mass×velocity ^ 2

Kinetic Energy (KE)=0.5×mass × velocity ^ 2

Joules = kg×m^2/s^2

1 mile = 1609.344 meters

1 hour = 3600 sec

1 Oz = 28.34952 g = 0.02834952 kg

a) KE=0.5×m×v^2

=0.5×(5.13 oz × 0.02834952 kg/1 ounce)×(95 miles/h × 1609.344 m/1 mile × 1 hr/3600 s)^2

=130.761 kg×m^2/s^2 = 130.761 Joules

b) KE=0.5×m×v^2

=0.5×(5.13 oz × 0.02834952 kg/1 ounce)×(54.8 miles/h × 1609.344 m/1 mile × 1 hr/3600 s)^2

=43.51028 kg×m^2/s^2 = 43.51028 Joules

= 130.761 / 43.51028 = 3.00528,  

As such the Kinetic Energy is approximately 3 times decreased