Answer:
Explanation:
Given
mas of car=870 kg
coffee mug mass=0.47 kg
coefficient of static friction between mug and roof 
Coefficient of kinetic Friction 
maximum car acceleration is 
here coefficient of static friction comes in to action because mug is placed over car . If mug is moving relative to car then \mu _k is come into effect

Ohm's Law tells the relationship between voltage, current, and resistance.
It can be written in three different ways, depending on which ones you know,
and which one you want to find.
Here's the one we need:
Resistance = (voltage) divided by (current)
= (120 V) / (0.5 Amp)
= 240 ohms .
Answer: True!
Explanation: The force is proportional to the square of the distance between 2 point masses