An amusement park ride raises people high into the air, suspends them for a moment, and then drops them at a rate of free-fall a
2 answers:
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Answer:
A)
B)
C)
Explanation:
This question is incomplete. The full question was:
<em>A skateboarder with mass ms = 54 kg is standing at the top of a ramp which is hy = 3.3 m above the ground. The skateboarder then jumps on his skateboard and descends down the ramp. His speed at the bottom of the ramp is vf = 6.2 m/s. </em>
<em>Part (a) Write an expression for the work, Wf, done by the friction force between the ramp and the skateboarder in terms of the variables given in the problem statement. </em>
<em>Part (b) The ramp makes an angle θ with the ground, where θ = 30°. Write an expression for the magnitude of the friction force, fr, between the ramp and the skateboarder. </em>
<em>Part (c) When the skateboarder reaches the bottom of the ramp, he continues moving with the speed vf onto a flat surface covered with grass. The friction between the grass and the skateboarder brings him to a complete stop after 5.00 m. Calculate the magnitude of the friction force, Fgrass in newtons, between the skateboarder and the grass.</em>
For part A), we make a balance of energy to calculate the work done by the friction force:
For part B), we use our previous value for the work:
Solving for friction force:
For part C), we first calculate the acceleration by kinematics and then calculate the module of friction force by dynamics:
Solving for a:
Now, by dynamics:
Answer:
a.
Explanation:
a. Find the probability that exactly one photo detector of a pair is acceptable:
Let photo is accepted and the probability
is defected.
Therefore:
#The probability of exactly one photo detector of a pair is accepted is 7/25
b.Find the probability that both photo detectors in a pair are defective,P(D1D2):
Hence, from out tree diagram,the probability that both photo detectors in a pair are defective is 6/25
Answer: 1 m/s
Explanation:
We have an object whose position is given by a vector, where the components X and Y are identified by the unit vectors
and
(where each unit vector is defined to have a magnitude of exactly one):
On the other hand, velocity is defined as the variation of the position in time:
This means we have to derive :
This is the velocity vector
And when the velocity vector is:
This is the velocity vector at 2 seconds
However, the solution is not complete yet, we have to find the module of this velocity vector, which is the speed :
Finally:
This is the speed of the object at 2 seconds