Answer:
-2.79 m/s²
Explanation:
Given:
v₀ = 20 m/s
v = 11 m/s
Δx = 50 m
Find: a
v² = v₀² + 2aΔx
(11 m/s)² = (20 m/s)² + 2a (50 m)
a = -2.79 m/s²
Round as needed.
1) Assuming an adult person has an average mass of m=80 kg, and assuming it takes about 30 seconds to climb 5 meters of stairs, the energy used by the person is

So the power output is

And since the estimate we made is very rough, we can say that the power output of the person is comparable to the power output of the light bulb of 100 W.
2) Based on the results we found in the previous part of the exercise, since the power output of the person is comparable to the power output of 1 light bulb of 100 W, we can say that the person could have kept burning only one 100-W light bulb during the climb.
Answer:
The change in potential energy and kinetic energy are 980 MJ and 148.3 MJ.
Explanation:
Given that,
Mass of aircraft = 10000 kg
Speed = 620 km/h = 172.22 m/s
Altitude = 10 km = 1000 m
We calculate the change in potential energy





For g = 10 m/s²,
The change in potential energy will be 1000 MJ.
We calculate the change in kinetic energy





For g = 10 m/s²,
The change in kinetic energy will be 150 MJ.
Hence, The change in potential energy and kinetic energy are 980 MJ and 148.3 MJ.
Answer:
F = 0.00156[N]
Explanation:
We can solve this problem by using Newton's proposed universal gravitation law.

Where:
F = gravitational force between the moon and Ellen; units [Newtos] or [N]
G = universal gravitational constant = 6.67 * 10^-11 [N^2*m^2/(kg^2)]
m1= Ellen's mass [kg]
m2= Moon's mass [kg]
r = distance from the moon to the earth [meters] or [m].
Data:
G = 6.67 * 10^-11 [N^2*m^2/(kg^2)]
m1 = 47 [kg]
m2 = 7.35 * 10^22 [kg]
r = 3.84 * 10^8 [m]
![F=6.67*10^{-11} * \frac{47*7.35*10^{22} }{(3.84*10^8)^{2} }\\ F= 0.00156 [N]](https://tex.z-dn.net/?f=F%3D6.67%2A10%5E%7B-11%7D%20%2A%20%5Cfrac%7B47%2A7.35%2A10%5E%7B22%7D%20%7D%7B%283.84%2A10%5E8%29%5E%7B2%7D%20%7D%5C%5C%20F%3D%200.00156%20%5BN%5D)
This force is very small compare with the force exerted by the earth to Ellen's body. That is the reason that her body does not float away.
Answer:
38.64 feet
Explanation:
x=x0 + vx0t + 1/2axt2
x= 0 + 0 + 1/2 X 32.17 ft/sec2 X 1.55 sec2
x = 38.64 feet