Download HW4 - Bryn Mawr College

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3.2
Sliding blocks with friction*
Mass Ma = 4 kg rests on top of mass MB = 5kg that rests on a fric-
tionless table. The coefficient of friction between the two blocks is
such that the blocks just start to slip when the horizontal force F
applied to the lower block is 27"Nÿ Suppose that now a horizontal
force is applied to the upper block. What is its maximum value for
the blocks to slide without slipping relative to each other?
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Synchronous orbit*
-3.4
Find the radius of the orbit of a synchronous sate!lite that circles
the Earth. (A synchronous satellite goes around the Earth once ev-
ery 24 h, so that its position appears stationary with respect to a
ground station.) The simplest way to find the answer mad give your
results is by expressing all distances in terms of the Earth's radius
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Mass and axle*
A mass m is connected to a vertica! revolving axle by two strings of
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length l, each making an angle of 45° with the axle, as shown. Both
, the axle and mass are revolving with angular velocity ÿo. Gravity
is directed downward.
(a) Draw a dear force diagram for m.
(b) Find the tension in the upper string, Tup, and lower string,
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f 3.8
Block and wedge*
A block rests on a wedge inclined at angle 0. The coefficient of
friction between the block and plane is u.
(a) Find the maximum value of 0 for the' block to remain
motionless on the wedge when the Wedge is fixed in position.
(b) The wedge is given horizontal acceleration a, as shown.
Assuming that tan 0 > ,u, find the minimum acceleration for the
block to remain on the wedge without sliding.
(c) Repeat part (b), but find the maximum value of the acceleration.
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3.17 Turning car*
A car enters amm whose radius is R. The road is banked at angle
0, and the coefficient of friction between the wheels and the road is
1ÿ. Find the maxirnam and minimum speeds for the car to stay on
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the road without skidding sideways.
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3.19 Mass and sprmgs
Find the frequency of oscillation of mass m suspended by two
springs having constants kÿ and k2, in each of the configurations
shown•
(a)
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