13. Explain whether the following answers are reasonable or not. Check the magnitude, the units, and the direction. You DO NOT have to solve the problems yourself.
a) A car speeds up as it enters the freeway. It accelerates at 5.4 m/s? What was the car's final speed?
ANSWER: 6.3 m/s forward
I

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.

An open cart is moving along a straight frictionless horizontal track. when rain starts falling vertically into the cart, what happens to the speed of the cart?

What are the necessary conditions for fusion?