The 0.14 kg tree topper is accidentally knocked off of a Christmas tree giving it an initial speed of 15 m/s . The tree topper ornament was initially at a height of 2.2 m above the ground and as falls it bumps into the leaves and the branches of the tree. If the work done by friction of the leaves and branches, on the ornamentis 3.6what is the speed of the ornament right as it hits the floor ?

(a)By what factor does the kinetic energy of a car increase when its speed doubles? triples? (b)  What happens to this kinetic energy in a car crash? (c)  Determine the speed a car is travelling if its kinetic energy is double what it would be at a highway speed limit of 100 km/h. (d)  Make up a cartoon to educate drivers about the relationships among speed, higher energy, and damage done in collisions.

In a time of T seconds, a motorcycle can accelerate from rest to the speed v. (a) Determine the amount of time (in terms of 7) required for it to accelerate from v to 6v if the power output remains constant. At = (b) Determine the speed of the motorcycle (in terms of v) 3T after starting. Vf=

A block of mass m= 5.00 kg is reased from point A and slides dows the frictionless track shown in the figure. calculate the speed of the block at piont B and C. g= 9.8m/s2

Mark and David are loading identical cement blocks ontoDavid’s pickup truck. Mark lifts his block straight up fromthe ground to the truck, whereas David slides his block upa ramp on massless, frictionless rollers. Which statement istrue? (a) Mark does more work than David. (b) Mark andDavid do the same amount of work. (c) David does morework than Mark. (d) None of these statements is necessarilytrue because the angle of the incline is unknown. (e) Noneof these statements is necessarily true because the mass ofone block is not given.

Hi please help with the following: After hitting a long fly ball that goes over the right fielder's head and lands in the outfield, the batter decides to keep going past second base and try for third base. The 59 kg player begins sliding 3.40 m from the base with a speed of 4.35 m/s. If the player comes to rest at third base, how much work was done on the player by friction?

Sam's job at the amusement park is to slow down and bring to a stop the boats in the log ride. If a boat and its riders have a mass of 1200 kg and the boat drifts in at 1.3 m/s how much work does Sam do to stop it? Express your answer in joules.

(a) How long (in s) will it take an 855 kg car with a useful power output of 36.0 hp (1 hp = 746 W) to reach a speed of 13.0 m/s, neglecting friction? (Assume the car starts from rest.) (b) How long (in s) will this acceleration take if the car also climbs a 2.80 m-high hill in the process? Additional Materials O Reading

WORK, ENERGY POWER P CA 0.2793 kg rocket in a fireworks display is launched from rest and follows an erratic flight path to reach the point P. Point P is 29 m above the starting point. In the process, 400 J of work is done on the rocket by the nonconservative force generated by the burning propellant. Ignoring air resistance and the mass lost due 29 m he Vo = 0 m/s to the burning propellant, find the speed vf of the rocket at the point P. ho