Download Noah Newton`s 2nd Law on Hills Class Exercises

Newton’s 2nd Law On Hills Class Exercises
Physics
1. i To reduce the risk of avalanches, park rangers set off explosives to start an avalanche when no one is near
the mountain. During one such procedure on a 55° slope, a 2500 kg block of snow separates from the ice
underneath it and slides down the hill. The coefficient of friction between the block of snow and the ice on the
slope is 0.3. The average sir resistance on the block of snow is 1000 N.
a) Draw a free body diagram of the block of snow
b) What is the net force acting on the block?
c) What is the block's acceleration?
d) How fast is the block going after travelling half a
kilometer down the mountain?
ii. When the avalanche is half a kilometer down the mountain, it breaks into 5 equal chunks. The average air
resistance on each chunk of snow is 900 N.
a) Draw a free body diagram of one the chunks
b) What is the net force acting on that chunk?
c) What is the acceleration of that chunk?
d) What is the velocity of that chunk after traveling
an additional half a kilometer down the slope?
2. Jimmy is going to pull his 1000 kg motorboat out of the water and up the 18° slope of the boat ramp.
i. Jimmy’s truck and boat trailer are parked on the boat ramp, 10 m uphill from the water. He gets in the truck,
eases off the brake, and allows the trailer to accelerate all the way down the ramp until it reaches the water
going 2 m/s. The coefficient of friction between the trailer and the ramp is 0.5.
a) Draw a free body diagram for the trailer as Jimmy
b) What is the acceleration of the trailer?
backs down the ramp.
c) What is the net force acting on the trailer?
d) What force does the truck apply to the trailer as
Jimmy backs the trailer down the ramp?
2. ii. After attaching the boat to the stationary trailer, Jimmy hits the truck’s gas pedal and the truck pulls the
trailer (and boat) up the ramp. When they get to the top of the 10 m long ramp, they are going 10 m/s.
a) Draw a free body diagram for the boat and
b) What is the trailer’s acceleration as it goes up the
trailer?
ramp?
c) What is net force acting on the trailer?
d) How much force does the truck exert on the
trailer as it pulls it up the ramp?
3 Michael and Anton are sliding a 150 kg big-screen TV up the 5 m long, 23° ramp of their moving truck.
i. If they start at rest at the bottom of the ramp, and each push with a force of 500N, they manage to get the TV
four meters up the ramp in 5 seconds.
a) Draw a free body diagram of the TV
b) What is the TV's acceleration as the boys push it
up the ramp?
c) What is the net force on the TV as the boys push it
up the ramp?
d) What is the force of friction acting on the TV on
the ramp?
e) What is the coefficient of friction between the
ramp and the TV?
f) How fast is the TV going when it is 4 m above the
ramp?
ii. With only one meter to go to the top of the ramp, Michael and Anton hear the jingle of an ice cream truck
coming down the street! The boys let go of the TV to search their pockets for loose change.
a) Draw the free body diagram of the TV after the
b) What is the net force on the TV after it is released?
boys let go.
c) What is the acceleration of the TV after it is
released?
d) How far up the ramp does the TV go before it
comes to a stop?
iii. The TV comes to a stop for a moment on the ramp and then begins to slide back down.
a) Draw a free body diagram for the TV as it comes
b) What is the net force on the TV?
back down the ramp
c) What is the TV's acceleration?
d) How fast is the TV going when it reaches the
bottom of the ramp?