A car of mass m travelling at 20
m/s east on a straight level road and a truck of mass 2m travelling at 20 m/s west on the same road. What is the velocity of the car relative to the truck?
Vc = 20 m/s.
Vt = -20 m/s.
Vc-Vt = 20 - (-20) = 20 + 20 = 40 m/s.
To find the velocity of the car relative to the truck, you need to find the difference between their velocities.
Given that the car is traveling east and the truck is traveling west, their velocities have opposite directions. Let's consider the direction of the car as positive (+) and the direction of the truck as negative (-).
The velocity of the car is 20 m/s east, which means it has a magnitude of 20 m/s in the positive direction. The velocity of the truck is 20 m/s west, which means it has a magnitude of 20 m/s in the negative direction.
To find the velocity of the car relative to the truck, subtract the magnitude of the truck's velocity from the magnitude of the car's velocity:
Velocity of car relative to truck = 20 m/s - (-20 m/s)
To subtract a negative number, you can think of it as adding the positive number:
Velocity of car relative to truck = 20 m/s + 20 m/s
Velocity of car relative to truck = 40 m/s
Therefore, the velocity of the car relative to the truck is 40 m/s in the east direction.