(A)energy lost in the lever due to friction
(C)
visual estimation of height of the beanbag
(E)position of the fulcrum for the lever affecting transfer of energy
Answer:
The acceleration is 2.2 m/s^2
Explanation:
In the attached image, we can see the free body diagram. And using the second law of Newton it will be possible to find the acceleration of the box.
An object's momentum is the product of its mass and its velocity:
p = mv
p is its momentum, m is its mass, and v is its velocity.
Given values:
p = -80kg×m/s
m = 8kg
Plug in these values and solve for v:
-80 = 8v
v = -10m/s
Choice D
Answer:
(a) work required to lift the object is 1029 J
(b) the gravitational potential energy gained by this object is 1029 J
Explanation:
Given;
mass of the object, m = 35 kg
height through which the object was lifted, h = 3 m
(a) work required to lift the object
W = F x d
W = (mg) x h
W = 35 x 9.8 x 3
W = 1029 J
(b) the gravitational potential energy gained by this object is calculated as;
ΔP.E = Pf - Pi
where;
Pi is the initial gravitational potential energy, at initial height (hi = 0)
ΔP.E = (35 x 9.8 x 3) - (35 x 9.8 x 0)
ΔP.E = 1029 J
Explanation:
First, we need to calculate the constant force, that is, the ratio between the applied force and the rubber stretch due to the application of the force:
![k=\frac{F}{d}(1)\\k=\frac{6N}{0.04m}\\k=150\frac{N}{m}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7BF%7D%7Bd%7D%281%29%5C%5Ck%3D%5Cfrac%7B6N%7D%7B0.04m%7D%5C%5Ck%3D150%5Cfrac%7BN%7D%7Bm%7D)
Now, we can know how far will an 18N force stretch the rubber. From (1):
![d=\frac{F}{k}\\d=\frac{18N}{150\frac{N}{m}}\\d=0.12m=12cm](https://tex.z-dn.net/?f=d%3D%5Cfrac%7BF%7D%7Bk%7D%5C%5Cd%3D%5Cfrac%7B18N%7D%7B150%5Cfrac%7BN%7D%7Bm%7D%7D%5C%5Cd%3D0.12m%3D12cm)
The work done by the external force on the rubber is equal to its elastic potential energy:
![W=\frac{kd^2}{2}\\W=\frac{150\frac{N}{m}(0.12m)^2}{2}\\W=1.08J](https://tex.z-dn.net/?f=W%3D%5Cfrac%7Bkd%5E2%7D%7B2%7D%5C%5CW%3D%5Cfrac%7B150%5Cfrac%7BN%7D%7Bm%7D%280.12m%29%5E2%7D%7B2%7D%5C%5CW%3D1.08J)