Question

A 58-kg boy swings a baseball bat, which causes a 0.140-kg baseball to move toward 3rd base with a velocity of 38.0 m/s.

Calculate the kinetic energy of the baseball (rounding your answer to the integer).

Answer 1

101 J

Step-by-step explanation:

Answer 2

`\boxed {\boxed {\sf 101 \ Joules}}`

Step-by-step explanation:

Kinetic energy can be found using the following formula:

`KE=(1)/(2)mv^2`

The mass of the baseball is 0.140 kilograms and the velocity is 38.0 meters per second.

`m= 0.140 \ kg \\v= 38.0 \ m/s`

Substitute the values into the formula.

`KE=(1)/(2) [0.140 \ kg][(38.0 \ m/s)^2]`

First, evaluate the exponent.

• (38.0 m/s)²= 38.0 m/s * 38.0 m/s = 1444 m²/s²

`KE=(1)/(2)(0.140 \ kg)(1444 \ m^2/s^2)`

Multiply the two numbers in parentheses together.

`KE=(1)/(2)(202.16 \ kg*m^2/s^2)`

Multiply the fraction by the number, or divide the number by 2.

`KE=101.08 \ kg*m^2/s^2`

Round to the nearest whole number. The 0 in the tenth place tells us we can leave the number as is.

`KE\approx 101 \ kg*m^2/s^2`

1 kg*m²/s² is equal to 1 Joule. Therefore, our answer of 101 kg*m²/s² is equal to 101 Joules (J).

`KE\approx 101 \ J`

The kinetic energy of the baseball is about 101 Joules.