A. The metal shield will heat up, and then heat the air on the student's side of the shield.
Answer:
C.The car appears to be moving 30 km/hr in the opposite direction of the bus.
Explanation:
There are two reference systems involved in this situation:
- Reference system S: this is the reference system where velocities are measured with respect to the ground. In this reference system, the car is parked, so its velocity is
- Reference system S': this is the reference system moving with the bus. This reference system is moving with a velocity of
with respect to the reference system S
Calling
the velocity of the car in the reference system S', we have:

From which

and the negative sign means that a passanger in the bus observes the car moving in the opposite direction.
Answer:
displacement=specific distance
*Velocity=∆displacement/time
*acceleration=∆velocity/time
The answer would be, "Granite".
The change in electric potential energy is given by:
ΔU = ΔVq
ΔU = change in PE, ΔV = potential difference, q = charge
Given values:
ΔV = 50V - 20V = 30V, q = 0.14C
Plug in and solve for ΔU:
ΔU = 30(0.14)
ΔU = 4.2J