What speed will the ball hit the ground?

In summary, a ball with a mass of 240g and initial velocity of 20.0m/s has a gravitational potential energy of 70J. Using the equations Ek=mv^2/2 and Eg=mgh, we can determine that the final velocity before hitting the ground is 31.4m/s. This is based on the assumption that the ground has zero potential and all the initial potential energy of 70J is converted to kinetic energy.
  • #1
SailorMoon01
7
0
A ball has a mass of 240g. (which would be 0.24kg?) is moving through the air at 20.0m/s with a gravitational potential energy of 70J. With what speed will the ball hit the ground.

Equations:

Ek=mv^2/2 (kinetic energy)
Eg=mgh (Gravitational potential energy)
Ek=mgxdisplacement (if you don't have velocity?)

I would appreciate ANY help...I don't get what I'm supposed to do.

P.S. the answer in the book says it should be 31.4m/s :)
 
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  • #2
You assume that the groud is zero potential: Then the initian kinetic energy is [itex]T_i =1/2mv_i^2[/itex]
And the initial potential energy is 70J the 70J is all being converted to kinetic energy when it falls so make your equation and solve it:
[itex] E_{initial}= 70J+T_i = E_{final}[/itex]
 
  • #3
Thank you :)
 

Related to What speed will the ball hit the ground?

1. What factors determine the speed at which a ball will hit the ground?

The speed at which a ball will hit the ground is primarily determined by the initial velocity of the ball, the angle at which it is thrown or dropped, and the force of gravity acting on the ball.

2. Does the weight of the ball affect its speed as it hits the ground?

Yes, the weight of the ball can affect its speed as it hits the ground. In general, a heavier ball will hit the ground with a greater force and therefore a higher speed.

3. How does air resistance impact the speed of a ball as it falls?

Air resistance can slow down the speed of a ball as it falls. This is because the air molecules exert a force on the ball in the opposite direction of its motion, causing it to slow down.

4. Is the speed at which a ball hits the ground affected by the surface it lands on?

Yes, the surface that a ball lands on can affect its speed. A softer surface, such as grass or sand, will absorb some of the impact and slow the ball down. A harder surface, like concrete or pavement, will not absorb as much of the impact and the ball will hit the ground at a higher speed.

5. Can the speed of a ball hitting the ground be calculated accurately?

Yes, the speed of a ball hitting the ground can be calculated accurately using the equations of motion. However, this calculation may be affected by variables such as air resistance and the elasticity of the ball and the surface it lands on.

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