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kelvin56484984
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Homework Statement
A)
An object moving along the x-axis is acted upon by a force Fx that varies with position as shown. How much work is done by this force as the object moves from x = 2 m to x = 8 m?
B)
A 50-kg child riding a Ferris wheel (radius of wheel R = 10 m) travels in a vertical circle. The wheel completes one revolution every 10 s. What is the magnitude of the force on the child by the seat at the highest point on the circular path?
C)
A 0.50-kg mass attached to the end of a string swings in a vertical circle (radius = 2.0 m). When the mass is at the lowestpoint on the circle, the speed of the mass is 12 m/s. What is the magnitude of the force of the string on the mass at this position?
D)
A 2.5-kg object falls vertically downward by 80 cm. How much work is done by the gravitational force on the object in this process?
E)
If vector A and B have magnitudes 12 and 15, respectively, and the angle between the two when they are drawn starting from the same point is 110, what is the scalar product of these two vectors?
Homework Equations
a=v^2/r
W=Fd
T=2*pi*r/v
The Attempt at a Solution
A)
positive area + negative area
1/2*20*4+1/2*(-10)*2
=30J
B)
T=2*pi/V
V=6.28 m/s
mg-N=m(v^2)/R
N=50*9.8-50*(6.28^2)/10
N=0.29kN
C)
T-mg=mv^2/R
T=(0.5*8^2)/2 +0.5*9.8
T=41N
D)
W=-(2.5*9.8*0.8)
W=-20J
E)
15*12*cos110
=-62
It said one of my answer is wrong .
Thank you