In a good hit, a baseball and bat are in contact with each other for about 1 millisecond. In the first game of the 2012 World Series, Tigers pitcher Justin Verlander threw a 100-mph pitch to the Giants' Pablo Sandoval. Sandoval's hit returned the ball directly back at Verlander at 70 mph. Calculate the average force of the bat on the ball, during the contact. Round the final answer to the nearest whole number.

Explanation:

100 mph = 100 x 1760 x 3 / ( 60 x 60 )

= 146.67 ft / s

70 mph = 70 x 1760 x 3 / ( 60 x 60 )

= 102.67 ft/s

Let mass of the ball = m .

The ball which was moving with a velocity of 146.67 ft/s is turned back by the action of force of bat on the ball and it moved in opposite direction with velocity of - 102.67 ft/s ( - ve sign due to reversed direction )

If m be the mass of ball

change in momentum = m x 146.67 - ( - m x 102.67 )

=  m x 146.67 +  m x 102.67

= 249.34 m

Change in momentum = impulse = force x time

Putting the given values

249.34 m = force x 1 x 10⁻³ ( time = 10⁻³ s )

force = 249.34 m x 10³ poundal .

Here m is mass of the ball in lb .

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.

the answer is ampere

the ampere is used to measure electricity. an ampere is a unit of electric current equal. a unit of measure for the flow of current in a circuit. one ampere is the amount of current flow provided when one volt of electrical pressure is applied against one ohm of resistance.