A physics professor pushes against a stationary wall, working up a sweat. Is he doing any actual physical work on the wall?
A) No--it's a law of nature that physics profs never do any actual work.
B) No, because the force by his hands against the wall is balanced by the force by the wall pushing back.
C) Yes, because he is exerting a force against the wall during a period of time.
D) No, because the wall is not moving.
E) Yes, because his arm muscles are moving other muscles through a distance.
Question 2
A projectile is fired from ground level with a speed of 150 m/s at an angle 30 above the horizontal on an airless planet where g = 10.0 m/s2. What is the horizontal component of its velocity after 4.0 s?
A) 38 m/s B) 75 m/s C) 150 m/s D) 130 m/s E) 35 m/s
great wall
Students working in a group
Ishtar Gate and Throne Room Wall "بوابة عشتار"
Physics - Density and Pressure
Physics
Physics