How come when I throw a tennis ball in the air and catch it while sitting in a car that's going fast...?

Question

...it falls back down but it doesn't fall back towards me at a great speed. Does that mean the car has its own gravitational force or something?

Answer 1

This is related to Newton's law: An object in motion or at rest will stay in motion or at rest unless acted upon by an external force.

To elaborate, an object travelling in a straight line will keep on travelling in that straight line at a constant speed unless something acts on it.

When you are in the car with your ball, everything in the car is travelling at the same speed, so you through the ball up and it comes straight back down. But if you throw the ball up and then jam on the cars brakes, the ball will keep moving at its original speed but the car is slowing down, so the ball would fly forward into the front windshield.

Last point, if you throw the ball out the window, it will appear to fly backwards - It is just slowing down compared to the car because unlike the air inside the car, the air outside is at rest, so the ball will be flying through the air at a high speed and the wind drag will slow it quite rapidly.

Answer 2

Uniform motion is absolutely no different than when you are rest. If you were to accelerate the car as the ball was in the air, it would indeed fall back toward you.

Consider that when you are standing on your lawn, you and the earth's surface are moving forward at over a thousand miles per hour - when you jump into the air, the earth does not move under you simply because you and the atmosphere surrounding you are also moving at the same speed.

An elevator is another good example - you are unaware of any motion during your trip up or down - you feel the motion only when it's uneven, when it first starts and when it comes to a stop.

Answer 3

You might as well be asking ..why is it when standing on earth and you jump in the air the earth doesn't spin around under your feet at a 1000mph. Silly isnt it. You and the ball move at the same horizonal velocity that the train moves. When you throw the ball up you will not change the balls horizontal velocity at all...it wont shot to the back of the train.

Answer 4

The ball is not going to 50 mph, the car is.

Think about what happens when you walk down the aisle of a moving train. Does your body go flying into the wall, no.

However, if the the train suddenly hit a wall, then the train's sudden loss of motion would cause serious injury.

Answer 5

the ball already has the same horizontal motion that you and the car do. it has nothing to do with the gravity of the car. if you were to throw the ball up while driving and then swerve or brake while the ball was in the air, the ball would not come back down to you, it would appear to be going in the opposite direction of the acceleration direction of the car (it would go forward if you were braking)

Answer 6

Things in motion tend to stay in motion. That is about the only thing I remember from my 9th grade physical science class 30 years ago.

Thank you Coach Collins.

Answer 7

no.......this is simple.....

its einsteins theory of relativity.......if you are in a car that is traveling 60 MPH........everything in that car is traveling 60 MPH....
including you....including the tennis ball.......if you were to throw the ball outside the car, you would whip by it immediately.....

Answer 8

if wind is not hitting the ball it will not go away from its destination.