Answer : The correct option is, 2880 J
Solution :
According to the question,
K.E + Energy lose to friction = P.E
![\text{Energy lose to friction}=P.E-K.E\\\\\text{Energy lose to friction}=mgh-\frac{1}{2}mv^2=m(gh-\frac{1}{2}v^2)](https://tex.z-dn.net/?f=%5Ctext%7BEnergy%20lose%20to%20friction%7D%3DP.E-K.E%5C%5C%5C%5C%5Ctext%7BEnergy%20lose%20to%20friction%7D%3Dmgh-%5Cfrac%7B1%7D%7B2%7Dmv%5E2%3Dm%28gh-%5Cfrac%7B1%7D%7B2%7Dv%5E2%29)
where,
m = mass of object = 60 Kg
g = acceleration due to gravity = ![9.8m/s^2](https://tex.z-dn.net/?f=9.8m%2Fs%5E2)
h = height = 10 m
v = velocity of an object = 10 m/s
Now put all the given values in the above formula, we get the energy lost to friction.
![\text{Energy lose to friction}=60Kg\times (9.8m/s^2\times 10m-\frac{1}{2}\times (10m/s)^2)=2880\text{ Kg }m^2/s^2=2880J](https://tex.z-dn.net/?f=%5Ctext%7BEnergy%20lose%20to%20friction%7D%3D60Kg%5Ctimes%20%289.8m%2Fs%5E2%5Ctimes%2010m-%5Cfrac%7B1%7D%7B2%7D%5Ctimes%20%2810m%2Fs%29%5E2%29%3D2880%5Ctext%7B%20Kg%20%7Dm%5E2%2Fs%5E2%3D2880J)
Therefore, the amount of energy she lose to friction is, 2880 J
Answer:
240
Explanation:
We know that Y is 800m from X, and located 400m north of X.
That means the cosine of the bearing of Y from X is 400m/800m = 1/2
We should remember (or use a calculator with arccos) that the angle for which the cosine is 1/2 is 60deg.
The bearing of Y from X is 060.
To get the bearing of X from Y, we just need to add or subtract 180 and we arrive at the answer - 240
Answer:
v = 12.3 m / s
Explanation:
This is an exercise in kinetics in one dimension
v² = v₀² + 2 a x
In this exercise they tell us that the initial velocity is (v₀ = 13 m / s), the acceleration is a = -0.95 m / s2 and the distance x = 9.2 m
we substitute
v = √ (13 2 - 2 0.95 9.2)
v = 12.3 m / s
note that as the acceleration is negative the vehicle is stopping