Answer:
a
When peter held the book for one minute the rate at which motor unites are fired increase steeply but as the duration increases the increese in the rate at which it is being fired becomes linear so the number of activated motors stay the same but are being activated at a more rapidly
b
The same motors are activated whilest he is hold the book for 2 minutes this is because for peter to hold the book in one fixed position one specific motor units need to be activated
Note changing the motor unites would change the positon of the hand
Explanation:
When a force acts on a body along some path, the work done is W=F*s, where W is the work done, F is the force that is doing the work on the body and s is the path. The force doing the work has to be in the same direction, or parallel, as the path. This is called positive work. If the force and the path are anti-parallel, the work is negative. So the relationship between work and force is W=F*s.
The mass of a is smaller than the mass of b.
Answer:
Radio Waves
Explanation:
Radio wave is a type of electromagnetic radiation notorious for their use in technologies used for communication like air traffic control, mobile phones, televisions and remote-controlled toys. Radio waves have the longest wavelength in the electromagnetic spectrum and are easily transmitted through air.
A radar gun uses radio waves to tell how far away an object is. To do that, the radar tool emits a focused radio wave and listens for any echo. If there is an item, say a car within the route of the radio wave, it's going to replicate some of the electromagnetic energy, and the radio wave will return to the radar gun. Radio waves flow via the air at a steady pace, so the radar gun can calculate how far the object is based totally on how long it takes the radio signal to return.
Answer:

Explanation:
<u>Work and Kinetic Energy
</u>
The work an object does due to its motion is equal to the change of its kinetic energy. Being ko and k1 the initial and final kinetic energy respectively and m the mass of the object, then

Since

We have

The truck has a mass of 60,000 kg and is moving at 27 m/s. The runaway truck ramp must stop the truck, so the final speed is 0. Thus


