The coefficient of kinetic friction for a 22 kg bobsled on a track is 0.10. What force is required to push it down a 5.0 degree
1 answer:
Hi there!
We must begin by converting km/h to m/s using dimensional analysis:
Now, we can use the kinematic equation below to find the required acceleration:
vf² = vi² + 2ad
We can assume the object starts from rest, so:
vf² = 2ad
(17.22)²/(2 · 75) = a
a = 1.978 m/s²
Now, we can begin looking at forces.
For an object moving down a ramp experiencing friction and an applied force, we have the forces:
Fκ = μMgcosθ = Force due to kinetic friction
Mgsinθ = Force due to gravity
A = Applied Force
We can write out the summation. Let down the incline be positive.
ΣF = A + Mgsinθ - μMgcosθ
Or:
ma = A + Mgsinθ - μMgcosθ
We can plug in the given values:
22(1.978) = A + 22(9.8sin(5)) - 0.10(22 · 9.8cos(5))
A = 46.203 N
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Answer:
a).
b).
Explanation:
a).
The work of the spring is find by the formula:
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Solve for K'
b).
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Answer:
a) is the height where the rocket stops accelerating and its fuel is finished and starts decelerating while it still continues to move in the upward direction.
b) is speed of the rocket going when it stops accelerating.
c)
d)
e) Zero, since the average velocity is the net displacement per unit time and when the rocket strikes back the earth surface the net displacement is zero.
Explanation:
Given:
acceleration of rocket,
time for which the rocket accelerates,
<u>For the course of upward acceleration:</u>
using eq. of motion,
where:
initial velocity of the rocket at the launch
height the rocket travels just before its fuel finishes off
so,
a) is the height where the rocket stops accelerating and its fuel is finished and starts decelerating while it still continues to move in the upward direction.
<u>Now the velocity of the rocket just after the fuel is finished:</u>
b) is speed of the rocket going when it stops accelerating.
After the fuel is finished the rocket starts to decelerates. So, we find the height of the rocket before it begins to fall back towards the earth.
Now the additional height the rocket ascends before it begins to fall back on the earth after the fuel is consumed completely, at this point its instantaneous velocity is zero:
using equation of motion,
where:
acceleration due to gravity
final velocity of the rocket at the top height
c) So the total height at which the rocket gets:
d)
Time taken by the rocket to reach the top height after the fuel is over:
Now the time taken to fall from the total height:
Hence the total time taken by the rocket to strike back on the earth:
e)
Zero, since the average velocity is the net displacement per unit time and when the rocket strikes back the earth surface the net displacement is zero.