Social Sciences, asked by Nareshk4582, 1 year ago

Potential energy is how many times kinetic energy

Answers

Answered by pandeylaxmi584
1

Energy

Energy is the capacity to do work.

The unit of energy is J (Joule) which is also kg m2/s2 (kilogram metre squared per second squared)

Energy can be in many forms! Here we look at Potential Energy (PE) and Kinetic Energy (KE).

Potential Energy and Kinetic Energy

hammer

A hammer:

when raised up has potential energy (the energy of position or state)

when falling down has kinetic energy (the energy of motion)

Potential energy (PE) is stored energy due to position or state

bow and arrow

a raised hammer has PE due to gravity.

fuel and explosives have Chemical PE

a coiled spring or a drawn bow also have PE due to their state

Kinetic energy (KE) is energy of motion

car moving

A moving car has a lot of kinetic energy

From PE to KE

skydivers

These skydivers have potential energy due to being high up.

After they jump this potential energy gets

converted into kinetic energy (and heat) as they speed up.

Gravitational Potential Energy

When the PE is due to an objects height then:

PE due to gravity = m g h

Where:

m is the objects mass (kg)

g is the "gravitational field strength" of 9.8 m/s2 near the Earth's surface

h is height (m)

hammer

Example: This 2 kg hammer is 0.4 m up. What is it's PE?

PE = m g h

= 2 kg × 9.8 m/s2 × 0.4 m

= 7.84 kg m2/s2

= 7.84 J

Kinetic Energy

The formula is:

KE = ½ m v2

Where

m is the object's mass (kg)

v is the object's speed (m/s)

car moving

Example: What is the KE of a 1500 kg car going at suburban speed of 14 m/s (about 50 km/h or 30 mph)?

KE = ½ m v2

KE = ½ × 1500 kg × (14 m/s)2

KE = 147,000 kg m2/s2

KE = 147 kJ

Let's double the speed!

car moving

Example: The same car is now going at highway speed of 28 m/s (about 100 km/h or 60 mph)?

KE = ½ m v2

KE = ½ × 1500 kg × (28 m/s)2

KE = 588,000 kg m2/s2

KE = 588 kJ

Wow! that is a big increase in energy! Highway speed is way more dangerous.

Double the speed and the KE increases by four times. Very important to know

moon

A 1 kg meteorite strikes the Moon at 11 km/s. How much KE is that?

KE = ½ m v2

KE = ½ × 1 kg × (11,000 m/s)2

KE = 60,500,000 J

KE = 60.5 MJ

That is 100 times the energy of a car going at highway speed.

From PE to KE

When falling, an object's PE due to gravity converts into KE and also heat due to air resistance.

Please mark as brainliest

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