A boat is traveling upstream at 14 mph with respect to a river that is flowing to the East at 6 mph (with respect to the ground). A man runs directly across the boat (the short side of the boat, in other words, running North relative to the boat), from one side to the other, at 6 mph (with respect to the boat). The speed of the man with respect to the ground is:
A) 10 mph B) 14 mph C) 18.5 mph D) 21 mph E) 26 mph
Can someone explain how this works. I don't really understand relative motion
A mass m1 = 5.3 kg rests on a frictionless table and connected by a massless string over a massless pulley to another mass m2 = 5.4 kg which hangs freely from the string. When released, the hanging mass falls a distance d = 0.87 m.
1)What is the final speed of the two blocks?
2)) How much work is done by tension on m1?
3)What is the tension in the string as the block falls?
4)The work done by tension on only m2 is:
5).What is the NET work done on m2?
A mass m = 17 kg rests on a frictionless table and accelerated by a spring with spring constant k = 5174 N/m. The floor is frictionless except for a rough patch. For this rough path, the coefficient of friction is μk = 0.53. The mass leaves the spring at a speed v = 2.8 m/s.
1) The mass is measured to leave the rough spot with a final speed vf = 1.1 m/s.
How much work is done by friction as the mass crosses the rough spot?
2)What is the length of the rough spot?
3).In a new scenario, the block only makes it (exactly) half-way through the rough spot. How far was the spring compressed from its unstretched length?
4)) In this new scenario, what would the coefficient of friction of the rough patch need to be changed to in order for the block to just barely make it through the rough patch?
5) Return to a scenario where the blcok makes it throgh the entire rough patch. If the rough patch is lengthened to a distance of three times longer, as the block slides through the entire distance of the rough patch, the magnitude of the work done by the force of friction is: