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girlphysics
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I need help with all of these. I am so lost on all of them and have been working for hours. Anything is so appreciated.
_____1. A rock is dropped off a cliff and falls the first half of the distance to the ground in t1 seconds. It falls the second half of the distance in t2 seconds. What is the value of t1/t2?
A) 1/2√2 B) 1/√2 C) ½
D) 1-(1/√2) E) √2-1
______2. A box of mass m slides on a horizontal surface with initial speed v0. It feels no forces other than it weight and the force from the surface. If the coefficient of kinetic friction between the box and surface is μ, how far does the box slide before coming to rest?
A) v02/2μg B) v02/μg C) 2v02/μg
D) mv02/μg E) 2 mv02/μg
_____3. An object initially at rest experiences a time-varying acceleration given by a = ( 2 m/s3 t) for t ≥ 0. How far does the oject travel in the first 3 seconds?
A) 9 m B) 12 m C) 18 m D) 24 m E) 27 m
______4. An engine provides 10kW of power to lift a heavy load at constant velocity a distance of 20 meters in 5 seconds. What is the mass of the load?
A) 100 kg B) 150 kg C) 200 kg D) 250 kg E)300 kg
______5. A ball (mass= .08 kg) is dropped onto the floor from a height of 2 m, and after bouncing off the floor rises almost to its original height. If the contact time with the floor was .04 s, what average force did the floor exert on the ball?
A) 0.16 N B) 16 N C) 25 N D) 36 N E) 64 N
_____1. A rock is dropped off a cliff and falls the first half of the distance to the ground in t1 seconds. It falls the second half of the distance in t2 seconds. What is the value of t1/t2?
A) 1/2√2 B) 1/√2 C) ½
D) 1-(1/√2) E) √2-1
______2. A box of mass m slides on a horizontal surface with initial speed v0. It feels no forces other than it weight and the force from the surface. If the coefficient of kinetic friction between the box and surface is μ, how far does the box slide before coming to rest?
A) v02/2μg B) v02/μg C) 2v02/μg
D) mv02/μg E) 2 mv02/μg
_____3. An object initially at rest experiences a time-varying acceleration given by a = ( 2 m/s3 t) for t ≥ 0. How far does the oject travel in the first 3 seconds?
A) 9 m B) 12 m C) 18 m D) 24 m E) 27 m
______4. An engine provides 10kW of power to lift a heavy load at constant velocity a distance of 20 meters in 5 seconds. What is the mass of the load?
A) 100 kg B) 150 kg C) 200 kg D) 250 kg E)300 kg
______5. A ball (mass= .08 kg) is dropped onto the floor from a height of 2 m, and after bouncing off the floor rises almost to its original height. If the contact time with the floor was .04 s, what average force did the floor exert on the ball?
A) 0.16 N B) 16 N C) 25 N D) 36 N E) 64 N