Find the gravitational potential energy

In summary, gravitational potential energy is the energy an object possesses due to its position in a gravitational field and is calculated using the formula PE = mgh or PE = mgy. It is measured in units of joules, foot-pounds, or kilowatt-hours. Gravitational potential energy and kinetic energy are both forms of mechanical energy and are directly related. The factors that affect the amount of gravitational potential energy an object has are its mass, the strength of the gravitational field, and its height above the ground.
  • #1
mustang
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Given: g=9.81 m/s^2.
A 41.7 kg child is in a swing that is attached to robes 2.16 m long. Find the gravitational potiental energy associated with the child relative to the child's lowest position under the following conditions:
B. when the ropes make a 34.7 degree angle with the vertical.

What equation would I use?
 
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  • #2
Well, potential energy = mgh looks good!

You might also want to draw a picture and use a little trigonometry to determine exactly what h is when the swing makes an angle of 34.7 degrees with the vertical.
 
  • #3


To find the gravitational potential energy of the child in this scenario, you would use the equation PE = mgh, where m is the mass of the child, g is the acceleration due to gravity (given as 9.81 m/s^2), and h is the height of the child above their lowest position. In this case, h would be equal to the vertical component of the ropes, which can be found using trigonometry as h = 2.16sin(34.7) = 1.23 m.

Plugging in the values, we get PE = (41.7 kg)(9.81 m/s^2)(1.23 m) = 509.5 J. Therefore, the gravitational potential energy associated with the child in this scenario is 509.5 joules.
 

What is gravitational potential energy?

Gravitational potential energy is the energy an object possesses due to its position in a gravitational field. It is directly related to an object's mass, the acceleration due to gravity, and the height at which it is located.

How is gravitational potential energy calculated?

The formula for gravitational potential energy is PE = mgh, where m is the mass of the object, g is the acceleration due to gravity, and h is the object's height above the ground. This formula can also be written as PE = mgy, where y is the vertical displacement from the ground.

What are the units of gravitational potential energy?

The SI unit for gravitational potential energy is joules (J). However, it can also be measured in other units such as foot-pounds (ft-lb) or kilowatt-hours (kWh).

How does gravitational potential energy relate to kinetic energy?

Gravitational potential energy and kinetic energy are both forms of mechanical energy. As an object falls, its potential energy decreases while its kinetic energy increases. At the maximum height, all of the energy is potential energy. At the lowest point, all of the energy is kinetic energy.

What factors affect the amount of gravitational potential energy an object has?

The amount of gravitational potential energy an object has is affected by its mass, the strength of the gravitational field, and its height above the ground. The greater the mass and height, the more potential energy an object will have. The strength of the gravitational field is determined by the mass of the larger object and the distance between the two objects.

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