Problem 39P

A marble column of cross-sectional area 1.2 m2 supports a mass of 25,000 kg. (a) What is the stress within the column? (b) What is the strain?

Nonconservative Forces Work Done By Nonconservative Forces ● In the presence of non-conservative forces, the total mechanical energy is not conserved: ○ W totalW conservativnonconservative ○ W = − ΔU + W = ΔK total nc ○ W nc ΔK + ΔU = ΔE Examples ● What height H must we release the car if it just makes it around the circular loop of radius R ● A shot put (m = 7.26 kg) is shot at an angle of 43.4 degrees and released from a height of 1.82 m above ground level then it lands with a final velocity of 20m/s. It lands a horizontal distance of 17.7 m from the release point. With what speed does the shot put leave the thrower’s hand ● A block of mass m1 = 2.40 kg is connected to a second block of mass m2 = 1.80 kg. When the blocks are released, they move through a distance d = 0.500 m at which point m2 hits the floor. The coefficient of friction between m1 and the table is 0.450. Find the speed of the blocks just before m2 lands. ● A 20.0 kg child slides down a 1.0m long slide inclined at 40.0o. The child starts at rest on the top and experiences a frictional force of 5.00 N. What is the speed of the child at the bottom of the slide ● An 80 kg jogger starts from rest and runs uphill in a stiff breeze. At the top of the hill the jogger has done a work W = 1.8 x 104 J, air resistance has done a work W = nc1