Desperately need help in work, energy and power question?
A heavy haulage truck is carrying a full load on a horizontal road at a speed of #23.3 kmh^-1# . The truck and load have a total mass of 8.79 tonnes. Total friction acting against the motion is #2.10 * 10^4 N# . What power must the truck's engine develop?
A heavy haulage truck is carrying a full load on a horizontal road at a speed of
2 Answers
The power is
Explanation:
The speed is constant
The acceleration is
Mass of the truck plus load is
The total frictional force is
According to Newton's Second Law
The power is
Explanation:
The mass of the truck and load is irrelevant. If it is travelling at constant velocity, it is not accelerating, so the force required is the force to overcome friction.
You may know that work,
#W = F * x#
And power
#P = W/t = ( F * x)/t = F * v#
So, being careful with the units: