Which statements apply to theories? check all that apply.
a theory is a factual statement.
b theory is well-tested and widely accepted.
c theory is an explanation.
d theory cannot be revised or replaced.
e theory can predict future events.

A1200 kg car traveling north at 10 m/s is rear-ended by a 2000 kg truck traveling at 30 m/s. what is the total momentum before and after the collision?

Anika asks eva to roll a basketball and then a bowling ball to her. which requires more force to roll, and why?

Ahair dryer is basically a duct in which a few layers of electric resistors are placed. a small fan pulls the air in and forces it through the resistors where it is heated. air enters a 1200 w hair dryer at 100 kpa and 22°c and leaves at 47°c. the cross-sectional area of the hair dryer at the exit is 60 cm2. neglecting the power consumed by the fan and the heat losses through the walls of the hair dryer, determine (a) the volume flow rate of air at the inlet and (b) the velocity of the air at the exit.