Hi, I was wondering why do in real life we refer our weight as for example 54kg instead of 540N? When we know that weight is a f
1 answer:
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1) 1.2 m/s
First of all, we need to find the angular velocity of the blade at time t = 0.200 s. This is given by
where
is the initial angular velocity
is the angular acceleration
Substituting t = 0.200 s, we find
Let's now convert it into rad/s:
The distance of a point on the tip of the blade is equal to the radius of the blade, so half the diameter:
And so now we can find the tangential speed at t = 0.200 s:
2)
The tangential acceleration of a point rotating at a distance r from the centre of the circle is
where is the angular acceleration.
First of all, we need to convert the angular acceleration into rad/s^2:
A point on the tip of the blade has a distance of
r = 0.400 m
From the centre; so, the tangential acceleration is
3)
The centripetal acceleration is given by
where
v is the tangential speed
r is the distance from the centre of the circle
We already calculate the tangential speed at point a):
v = 1.2 m/s
while the distance of a point at the end of the blade from the centre is
r = 0.400 m
Therefore, the centripetal acceleration is
The question is incomplete! The complete question along with answer and explanation is provided below.
Question:
A 0.5 kg mass moves 40 centimeters up the incline shown in the figure below. The vertical height of the incline is 7 centimeters.
What is the change in the potential energy (in Joules) of the mass as it goes up the incline?
If a force of 1.0 N pulled up and parallel to the surface of the incline is required to raise the mass back to the top of the incline, how much work is done by that force?
Given Information:
Mass = m = 0.5 kg
Horizontal distance = d = 40 cm = 0.4 m
Vertical distance = h = 7 cm = 0.07 m
Normal force = Fn = 1 N
Required Information:
Potential energy = PE = ?
Work done = W = ?
Answer:
Potential energy = 0.343 Joules
Work done = 0.39 N.m
Explanation:
The potential energy is given by
PE = mgh
where m is the mass of the object, h is the vertical distance and g is the gravitational acceleration.
PE = 0.5*9.8*0.07
PE = 0.343 Joules
As you can see in the attached image
sinθ = opposite/hypotenuse
sinθ = 0.07/0.4
θ = sin⁻¹(0.07/0.4)
θ = 10.078°
The horizontal component of the normal force is given by
Fx = Fncos(θ)
Fx = 1*cos(10.078)
Fx = 0.984 N
Work done is given by
W = Fxd
where d is the horizontal distance
W = 0.984*0.4
W = 0.39 N.m
