Download PHYS101 Unit 2questions and answers Graded A+ and more Exams Physics in PDF only on Docsity!
PHYS101 Unit 2questions and answers Graded
A+
a 900 kg chevy truck has 27,000 kg m/s of momentum. how fast is it moving? - ✅✅30 m/s (use momentum formula: p=mv) my head hurts less when hitting an airbag than when hitting the windshield because - ✅✅impact force is decreased a 10 kg chunk of putty moving at 3 m/s collides and sticks to a 5 kg bowling ball initially at rest. the bowling ball and putty then move with a speed of - ✅✅ 2 m/s (use conservation of momentum-- p(initial)=p(final)) momentum is measured in units of - ✅✅kg m/s superman (80 kg) throws an 80,000 kg asteroid towards the sun at 2 m/s. if they both started at rest, how fast does superman travel backwards after the throw? - ✅✅2,000 m/s (use conservation of momentum) two identical freight trains are moving towards each other on the tracks at a high rate of speed. what is the total momentum of that system? - ✅✅0 kg m/s how long would it take to stop a 1500 kg racecar moving at 10 m/s using a braking force of 4000 N? - ✅✅3.75 s (impulse = Ft=p) how much potential energy does my 200 kg sister have sitting in a tree 3m off the ground? - ✅✅6000 J (PE=mgh)
if i push on a 50 kg sled with 100 N of force for 10 m, how fast is it going if it started from rest? - ✅✅6.3 m/s (find work-- work=f x d, then solve for velocity using the KE formula-- KE=1/2mv^2) how long could i run a 1500 W hairdryer with 475,000 J of energy? - ✅✅317 s (power=energy/time) i drop my 200 kg sister from rest off of a tower that stands at 20 m high. what is her kinetic energy at the top of the tower? - ✅✅0 J i drop my 200 kg sister from rest off of a tower that stands at 20 m high. what is her potential energy at the top of the tower? - ✅✅40,000 J i drop my 200 kg sister from rest off of a tower that stands at 20 m high. what is her kinetic energy at a height of 5 m from the ground? - ✅✅30,000 J i drop my 200 kg sister from rest off of a tower that stands at 20 m high. what is her potential energy at a height of 5 m from the ground? - ✅✅10,000 J mass is 200 kg and the height is 20 m. what is her velocity at a height of 5 m from the ground? - ✅✅17.3 m/s which requires more work: lifting a 50 kg sack vertically 2 m or lifting a 25 kg sack vertically 5 m? - ✅✅lifting the 25 kg sack
centripetal forces that make objects move in circles do so by - ✅✅changing the direction of the object in a turn a freight train rolls along a track with considerable momentum. if it rolls at the same speed but has twice as much mass, its momentum is - ✅✅doubled a rifle recoils while firing a bullet. the speed of the rifle's recoil is small because the - ✅✅rifle has much more mass than the bullet a 4 kg ball has a momentum of 12 kg m/s. what is the ball's speed? - ✅✅3 m/s a ball is moving at 3 m/s and has a momentum of 48 kg m/s. what is the ball's mass? - ✅✅16 kg a 1000 kg car moving at 10 m/s brakes to stop in 5 sec. the average breaking force is - ✅✅2000 N a 5 kg fish swimming at a speed of 1 m/s swallows a 1 kg fish at rest. the speed of the larger fish after this lunch is - ✅✅5/6 m/s an astronaut, floating alone in outer space, throws a baseball. if the ball floats away at a speed of 20 m/s, the astronaut will - ✅✅move in the opposite direction, but at a lower speed (astronaut has a larger mass) when you jump from an elevated position you usually bend your knees upon reaching the ground. by doing this, you make the time of the impact about 10
times as great as for a stiff-legged landing. in this way, the avg force your body experiences is - ✅✅about 1/10 as great compared to falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because the - ✅✅stopping time is longer on the carpet a job is done slowly, while an identical job is done quickly. both jobs require the same amount of work, but different amounts of - ✅✅power do 100 J of work in 50 s and your power output is - ✅✅2 W a 1000 kg car and a 2000 kg car are hoisted the same distance. raising the more massive car requires - ✅✅twice as much work a car that travels twice as fast as another when braking to a stop will skid - ✅✅four times as far when an automobile is braked to stop, its kinetic energy is transformed to - ✅✅heat a diver who weighs 500 N steps off a diving board that is 10 m above the water. the diver hits the water with a kinetic energy of - ✅✅5000 J (convert N to kg) horses that move with the fastest linear speed on a merry-go-round are located - ✅✅near the outside
when a twirling ice skater brings her arms inward, her rotational speed - ✅✅increases a 1 kg rock is suspended from the tip of a meter stick at the 0 cm mark so that the meter stick balances like a see-saw when the fulcrum is at the 25 cm mark. from this info, what is the mass of the meter stick? - ✅✅1 kg according to newton, when the distance between two interacting objects doubles, the gravitational force is - ✅✅one-quarter (if they get twice as closer, the force would be 4x as much) according to newton, the greater the masses of interacting objects, the - ✅✅greater the gravitational force between them what is the force on a 500 N woman standing on earth's surface? - ✅✅500 N when the distance between two stars decreases by one-third, the force between them - ✅✅increases to nine times as much the planet jupiter is about 300 times as massive as earth, yet on its surface you would weight only about 3x as much because - ✅✅jupiter's radius is about 10x the earth's radius a black hole is - ✅✅the remains of a giant star that has undergone gravitational collapse
where is the tension pointed to in order to change direction to move in a circle? - ✅✅the center what is moment arm? - ✅✅the distance from the force to the center of rotation true or false: everything has the same angular momentum, but linear speed is different - ✅✅true
