if you push a box across the floor its "physics works" but if you push on the wall its not. which of the following choices best explains why?

A father and his young daughter are ice skating. They faceeach other at rest and push each other, moving in oppositedirections. Which one has the greater final speed? Explain.

In England in the Middle Ages an extensive system of canals was used for transportation. Some of these canals crossed over canyons by flowing over bridges (viaducts). Suppose that a heavily loaded barge crossed over such a waterway bridge. A) The force on the barge would become less because some water would be squeezed off of the bridge. B) The force downward on the bridge would increase because of the added weight of the barge. C) The force on the bridge would not change when the barge passed over. D) The force on the bridge would become less because of the buoyancy effect of the water on the barge. E) Whether or not the force on the bridge would increase or decrease would depend on whether the water was flowing or stationary.

I get the first one where logically even though the bug splats on the car it can never exert more force on the car as you might intuitively think but I don't get part 2 of the mosquito question.

12. How much force would a car's tires need to provide to accelerate an 1800 kg car at a rate of 4.0 m/s?? Your answer: O 39 N O 450 N 1800 N O 7200 N

Suppose that an astronaut in space while working in the Hubble Telescope in space hitsaccidentally his thumb with the weightless hammer. Would it hurt? Explain.

A bowling ball of mass m=2.6 kg drops from a height h = 12 m. A semi-circular tube of radius r = 5.4 m rest centered on a scale. A) Write an expression for the reading of the scale when the bowling ball is at its lowest point, in terms of the variable in the problem statement B) What does the scale read in newtons.

A 200 N force due East and a 80N force due West both act on an object.  The object accelerates due East at 6N/kg. The mass of the object is

I don't know what force is acting on. I thought it would be force of friction, but I guess I'm wrong as I didn't get a right answer.

A mother and her 5-year old daughter are ice skating. While at rest, they face each other then push off eachother with their hands, sending them in opposite directions. Assuming the mother weighs much more than thedaughter, what motion results? The mom accelerates faster because she could push with more force. The little girl accelerates faster because her mom pushed her with more force. They both accelerate at the same rate because their forces are equal and opposite. Although the forces are equal and opposite, mom has more inertia. Hence momtravels slower than the daughter