A machine can never be 100% efficient because some work is always lost due to what?
2 answers:
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To solve this problem it is necessary to apply the concepts related to Normal Force, frictional force, kinematic equations of motion and Newton's second law.
From the kinematic equations of motion we know that the relationship of acceleration, velocity and distance is given by
Where,
Final velocity
Initial Velocity
a = Acceleration
x = Displacement
Acceleration can be expressed in terms of the drag coefficient by means of
Frictional Force
Force by Newton's second Law
Where,
m = mass
a= acceleration
Kinetic frictional coefficient
g = Gravity
Equating both equation we have that
Therefore,
Re-arrange to find x,
The distance traveled by the car depends on the coefficient of kinetic friction, acceleration due to gravity and initial velocity, therefore the three cars will stop at the same distance.
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