Trisha works for a roofing company and needs to move shingles from the ground to the roof.
2 answers:
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Answer:
Vi = 32 [m/s]
Explanation:
In order to solve this problem we must use the following the two following kinematics equations.
The negative sign of the second term of the equation means that the velocity decreases, as indicated in the problem.
where:
Vf = final velocity = 8[m/s]
Vi = initial velocity [m/s]
a = acceleration = [m/s^2]
t = time = 5 [s]
Now replacing:
8 = Vi - 5*a
Vi = (8 + 5*a)
As we can see we have two unknowns the initial velocity and the acceleration, so we must use a second kinematics equation.
where:
d = distance = 100[m]
(8^2) = (8 + 5*a)^2 - (2*a*100)
64 = (64 + 80*a + 25*a^2) - 200*a
0 = 80*a - 200*a + 25*a^2
0 = - 120*a + 25*a^2
0 = 25*a(a - 4.8)
therefore:
a = 0 or a = 4.8 [m/s^2]
We choose the value of 4.8 as the acceleration value, since the zero value would not apply.
Returning to the first equation:
8 = Vi - (4.8*5)
Vi = 32 [m/s]
When you're using a crowbar to lift a large rock, you are working against the force called
Gravity on Earth is what gives weight to all objects, it's defined as all things that have mass or energy are gravitated towards each other. Therefore when you're using a crowbar to lift a large rock, the weight is caused by gravity.
I hope this helps you!
Gravity on Earth is what gives weight to all objects, it's defined as all things that have mass or energy are gravitated towards each other. Therefore when you're using a crowbar to lift a large rock, the weight is caused by gravity.
I hope this helps you!
Answer:
50
Explanation:
The mechanical advantage of a machine is given by
where
is the output force
is the input force
For the crowbar in this problem,
is the force in input applied by the worker
is the force that the machine must apply in output to overcome the resistance of the window and to open it
Substituting into the equation, we find