A weightlifter lifts a 50 kg bar from the floor to a position over his head and back to the floor again 10 times in succession. At the end of this exercise, what energy transformations have taken place?

Scenario: Some Marines are lowering a 170 kg sled loaded with ammunition down a hill, when the rope breaks and the sled begins sliding uncontrolled. Beginning with a speed of 1.9 m/s, the sled loses 4.3 meters of elevation before coming to a stop. Question: How much thermal energy (in joules) was generated in the sled and the hill during the slide?

Six blocks with different masses, m, each start from rest at the top of smooth, frictionless inclines having length d and vertical height h and slide down. Rank the order, from greatest to smallest, of the final kinetic energies of the masses when they reach the bottom of the inclines after having traveled their full lengths. If any of the situations yield the same kinetic energies, give them the same ranking. (Use only ">" or "=" symbols. Do not include any parentheses around the letters or symbols.) m = 90 kg; h = 4 m; and d = 30 m m = 90 kg; h = 4 m; and d = 15 m m = 45 kg; h = 2 m; and d = 30 m m = 9 kg; h = 8 m; and d = 15 m m = 9 kg; h = 2 m; and d = 15 m m = 135 kg; h = 3.0 m; and d = 22.5 m

Gym Bro snatched 100 kg. In a snatch, the barbell is moved from a stationary position on the floor to the stationary position over Gym Bro’s head (and he screams during it, because that’s the Bro way).  Only 0.50 s elapsed from the first movement of the barbell until it was overhead, and the barbell moved through a vertical displacement of 2.0 m.  What was Gym Bro’s average power output during the lift?  Why is he too cool to rerack his weights?????

Samantha wishes to maintain her weight and goes to the gym to work off the calories she consumed at breakfast that morning. She lifts a 28.0-kg barbell from shoulder level to above her head, through a vertical height of 0.550 m. How many times must she lift the barbell to make up for the 3.25  102 Calories of energy she consumed at breakfast? Note that Calories refers to food calories. (Include lowering the barbell as well.) The answer is NOT 9

After finishing 2 fried eggs, a sausage, and a cup of latte as breakfast at 8:30 am, Nancy starts biking at constant speed of 15 km/h. Food Energy content in Cal Fried egg 100 Sausage 286 Latte 260 Big apple 125 Slice of 380 pepperoni pizza 12 oz soda 160 Activity Metabolic power (W) Cycling at 15 km/h 400 Walking at5 km/h 280 a) What time Nancy will use up all the intake energy due to biking? b) If Nancy decide to walk back at 5 km/h for an hour then bike at 15 km/h, how many slice of pizza she needs to eat together with a can of 12 oz soda and a big apple as lunch?

I drive a Nissan Leaf to work. With the e-pedal on, the motor recovers energy through braking very aggressively. I need about 7 KW-hour to come to school if I use mostly the freeways. That’s about 5 KW-hour if I take mostly local streets. From the energy perspective, can you offer an explanation to explain this difference?

When jogging at 13 km/h on a level surface, a 70-kg man uses energy at a rate of approximately 850 W. Using the facts that the “human engine” is approximately 25% efficient, determine the rate at which this man uses energy when jogging up a 5.0° slope at this same speed. Assume that the frictional retarding force is the same in both cases.

Which of the following pairs of particles will have NO ELECTROSTATIC INTERACTION? Choose all that apply. 02 electrons 2 negative ions A neutrino & a negative ion A proton & a neutrino A negative ion & a -1000 μC charge DA +839 μC charge & a -272 μC charge DA proton & a positive ion A-774 μC charge & a -240 μC charge

What is the kinetic energy of a 1.2 x 10°kg car whose velocity is 35 Km/hr?