Answer: When the car speed triples, momentum also triples but Kinetic energy increases 9 times or by 9 fold.
Explanation:
The momentum of a car (an object) is
p= mv
where
m is =the mass of the object( in this case car)
v is its= velocity
While the kinetic energy is is given by the formulae
K=1/2mv²
To determine how momentum and kinetic energy of the car changes when the speed of the object triples, We have that the new velocity,
v¹= 3v
So that the momentum change becomes
p¹=mv¹=m (3v)= 3mv
mv=p
therefore p¹= 3p
we can see that the momentum also triples.
And the kinetic energy change becomes
K¹=1/2m(v¹)²= 1/2m (3v)²
= 1/2m9v²= 1/2 x m x 9 x v²=9 x1/2mv²
1/2mv²=K
K¹= Kinetic energy = 9k
but Kinetic energy increases 9 times
Answer:
a) 0 metres
b) From time 0 s to 10 s , the car was accelerated. Its velocity accelerated from 0m/s to 20 m/s
c) 20 m/s
Explanation:
a) <em>Formula of displacement= velocity x time</em>
time=40 s
velocity =0 m/s
∴ displacement= 0 x 40 = 0 m
Magnitude of displacement is 0 m
b) The increase in velocity shows that there has been acceleration.
c) The average velocity of the car is =
{initial velocity + final velocity}
=
=20
Therefore, the magnitude of the average velocity of the car is 20 m/s
KE=1/2 m v^2
KE= .5 x 2kg x 15m/s to the 2nd power
KE=225 km/s
