The work required to raise an object to a height is equal to the gravitational potential energy the object gains. <em>(C)</em>
Acceleration = (change in speed) / (time for the change)
change in speed = (speed at the end) - (speed at the beginning)
Our cyclist's change in speed = (3 m/s) - (8 m/s) = -5 m/s
Acceleration = (-5 m/s) / (60 seconds)
<em>Acceleration = -1/12 m/s²</em>
The force between two charges is proportional to the product of the charges.
If only one of the charges is reduced by a factor of 3, then the force is reduced by a factor of 3.
If both charges are reduced by a factor of 3, then the force is reduced by a factor of 9.
D = vo t - at²/2
v = vo - at
40 m = vo · 7.10 - a · ( 7.10 )²/2
40 m = 7.10 vo - a· 50.41/2
40 m = 7.10 vo - 25.205 a
2.75 m/s = vo - 7.10 a ⇒ a = ( vo - 2.75 )/ 7.10
40 = 7.10 vo - 25.205 · ( vo - 2.75 ) / 7.10
40 = 7.1 vo - 3.55 vo + 9.7625
3.55 vo = 30.2375
vo = 30.2375 : 3.55 = 8.5176 m/s
Answer: the truck`s original speed is 8.5176 m/s.
The answer is 80 J of electrical energy
