Answer:
1.56 J
Explanation:
The potential energy only depends on the vertical height from the ground level.
We consider the ground level to have zero P.E.
So when it is 2 m above the ground level,
P.E. = mgh
= 0.078×10×2
= 1.56 J
Answer:
t = 12s
Explanation:
Given:
v-initial = 0 m/s
x = 360 m
a = 5.0 m/s^2
Solve:
x = (v-initial)t + 1/2(a*t^2)
360 = 0t + 1/2 (5.0t^2)
360 = 2.5 t^2
144 = t^2
t = sqrt(144) = 12
Therefore, it takes 12 seconds.
Answer:
f = 19,877 cm and P = 5D
Explanation:
This is a lens focal length exercise, which must be solved with the optical constructor equation
1 / f = 1 / p + 1 / q
where f is the focal length, p is the distance to the object and q is the distance to the image.
In this case the object is placed p = 25 cm from the eye, to be able to see it clearly the image must be at q = 97 cm from the eye
let's calculate
1 / f = 1/97 + 1/25
1 / f = 0.05
f = 19,877 cm
the power of a lens is defined by the inverse of the focal length in meters
P = 1 / f
P = 1 / 19,877 10-2
P = 5D
