When a car’s speed doubles, what happens to its kinetic energy? When its speed triples? If a car’s speed doubles, its kinetic energy increases by 4, if its speed triples then the kinetic energy increases by 9.

## How efficient is a typical gasoline burning car engine?

Most internal combustion engines are incredibly inefficient at turning fuel burned into usable energy. The efficiency by which they do so is measured in terms of “thermal efficiency”, and most gasoline combustion engines average around 20 percent thermal efficiency.

## How much power is expended if you lift?

Lifting Weights: If it takes 1 second to lift the weight 1 meter, than you have converted 10 Joules of energy to potential energy in one second. That’s 10 Watts of power. If you lift a 2 kg weight 1 meter in 1 second, then the rate of energy conversion is 2 x 10 = 20 Joules per second, or 20 Watts of power.

## Is the ratio of useful work output to work input?

The efficiency of a machine is the ratio of useful energy output to total energy input, or the percentage of the work input that is converted to work output. Efficiency can be expressed as the ratio of useful work output to total work input.

## Why is the efficiency of a machine always less than 100 %?

The percentage of the work input that becomes work output is the efficiency of a machine. Because there is always some friction, the efficiency of any machine is always less than 100 percent.

## At what point in its swing is kinetic energy a maximum?

The kinetic energy is maximum at the bottom of the swing, where the gravity potential energy is minimum. The pendulum continues to swing up, slowing down and losing kinetic energy as gravity potential energy.

## At what point is potential energy the greatest?

Gravitational potential energy is the energy that an object has because of its height and is equal to the object’s mass multiplied by its height multiplied by the gravitational constant (PE = mgh). Gravitational potential energy is greatest at the highest point of a roller coaster and least at the lowest point.

## Why does a pendulum swing faster with a shorter string?

The length of the string affects the pendulum’s period such that the longer the length of the string, the longer the pendulum’s period. A pendulum with a longer string has a lower frequency, meaning it swings back and forth less times in a given amount of time than a pendulum with a shorter string length.

## Do longer pendulums swing faster?

Length. The swing rate, or frequency, of the pendulum is determined by its length. The longer the pendulum, whether it is a string, metal rod or wire, the slower the pendulum swings. Conversely the shorter the pendulum the faster the swing rate.

## What is law of isochronous?

A sequence of events is isochronous if the events occur regularly, or at equal time intervals. In horology, a mechanical clock or watch is isochronous if it runs at the same rate regardless of changes in its drive force, so that it keeps correct time as its mainspring unwinds or chain length varies.

## What is the ideal simple pendulum?

An ideal simple pendulum is a heavy point mass suspended from a rigid support by a weightless, inextensible and twistless string , and set oscillating under gravity through a small angle in a vertical plane.

## What is the definition of time period?

The time period is the time taken by a complete cycle of the wave to pass a point, Frequency is the number of complete cycle of waves passing a point in unit time.

## Why simple pendulum is called simple?

1 Answer. In the case of a simple pendulum (also called a mathematical pendulum of simple gravity pendulum), one assumes that all of the mass is the bob and the rest of the pendulum is massless. This pendulum gives the easiest way te look at harmonic motion. The above case is what they call the simple pendulum.

Galileo

Galileo Galilei