Question

A baseball weighs 5.13 oz. what is the kinetic energy, in joules, of this baseball when it is thrown by a major league pitcher at 95.0 mi/h

Answer 1

The kinetic energy of a baseball weighing 5.13 oz (which converts to 0.145 kg) and thrown at 95.0 mi/h (which converts to 42.47 m/s) is approximately 131.1 Joules.

Step-by-step explanation:

To find the kinetic energy of a baseball thrown by a major league pitcher at 95.0 mi/h, we first need to convert the velocity to SI units (meters per second), and the mass of the baseball to kilograms (kg).

Step 1: Convert the baseball's weight to kilograms: 5.13 oz = 0.145 kg (5.13 oz × 0.0283495 kg/oz).

Step 2: Convert velocity from mi/h to m/s: 95.0 mi/h = 42.47 m/s (95.0 mi/h × 1.60934 km/mi × 1000 m/km × 1/3600 s/h).

Step 3: Use the kinetic energy formula KE = 0.5 × m × v². Insert the mass and velocity values into the formula.

Step 4: Calculate the kinetic energy: KE = 0.5 × 0.145 kg × (42.47 m/s)² = 131.1 Joules.

The kinetic energy of the baseball when thrown at 95.0 mi/h is approximately 131.1 Joules.

Answer 2

Let's convert all the quantities into S.I. units:
Mass of the ball:
`m=5.13 oz=0.15 kg`
Speed of the ball:
`v=95.0 mi/h=42.5 m/s`

The kinetic energy of the ball is given by

`K= (1)/(2)mv^2`
where m is the mass and v the speed. Substituting the data of the problem, we find

`K= (1)/(2)(0.15 kg)(42.5 m/s)^2=135.5 J`