A test car travels in a straight line along x axis. The figure below shows the car’s position x as a function
of time. Find:
=6s
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=3s, t
1
=5s and t
2
=Os, t
0
a) Position of the car at t
and t
1
2
b) x-component of car’s displacement and average velocity during time interval from to to t
3
tot
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2
=ls and t
1
c) x-component of instantaneous velocity of the car at points t
2
t
1 to
d) x-component of average acceleration during time interval from t
x(m)
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An airplane is dropping bales of hay to cattle stranded in a blizzard on the Great Plains. The pilot
releases the bales at 150m above the level ground when the plane is flying at 75m/s in a horizontal path.
a) What is the initial velocity (x, y components) of the bail?
b) How far in front of the cattle should the pilot to release the hay so that the bales will land at the
point where the cattle are stranded?
c) What is the speed of the bail just before it touches the ground?
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A basketball player Darrell Griffith is on record as attaining a standing vertical jump of 1.2m (this means
that he moved upward by 1.2 m after his feet left the floor). Griffith weighed 890N
a) What was his speed as he left the floor
b) If the time of the part of the jump before his feet left the floor was O.3s, what were the
magnitude and the direction of his acceleration (assuming it to be constant) while he was
pushing against the floor?
c) Draw a free body diagram of Griffith during the jump for each case (while his feet touching the
d)
e)
ground and after his feet left the ground).
What is his mass and what would be his mass and weight on Moon? (acceleration due to gravity
on Moon is 1.6m/s
)
2
Use Newton’s laws and the result from b) to calculate the force exerted on him by floor during
his jump.
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Two boxes are connected by a light string that passes over a light, frictionless pulley. One box rests on a
frictionless ramp that is raises a 300 above the horizontal, and the system is released from rest.
a) Make a free body diagrams for each box and put reference frames to be used
0 and acceleration
b) If the 50kg box at t=2s was moving up along the ramp (see figure) with speed v
0 what would be the direction (show in the drawing) and magnitude of the velocity and
a
acceleration of the 30kg box.
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