Answer:
2255 days
Explanation:
height, h = 1.8 km = 1800 m
amount of water, m = 3.2 x 10^7 kg
Power, P = 2.9 kW = 2900 W
Let t be the time taken
Energy required to lift the water,
E = m g h
E = 3.2 x 10^7 x 9.8 x 1800 = 5.65 x 10^11 J
Power, P = Energy / time
t = E / P = (5.65 x 10^11) / 2900
t = 1.95 x 10^8 second
t = 2255 days
thus, the time taken is 2255 days.
Explanation:
In brief, electrons are negative charges and protons are positive charges. An electron is considered the smallest quantity of negative charge and a proton the smallest quantity of positive charge.
Two negative charges repel. Also, two positive charges repel. A positive charge and a negative charge attract each other (all experimentally verified.)
Point Charge: An accumulation of electric charges at a point (a tiny volume in space) is called a point charge.
Note: When an atom loses an electron, the separated electron forms a negative charge, but the remaining that contains one less electron or consequently one more proton becomes a positive charge. A positive charge is not necessarily a single proton. In most cases, a positive charge is an atom that has lost one or more electron(s).
Answer:
a. a = 
b. T = -0.81 N
Explanation:
Given,
- weight of the lighter block =

- weight of the heavier block =

- inclination angle =

- coefficient of kinetic friction between the lighter block and the surface =

- coefficient of kinetic friction between the heavier block and the surface =

- friction force on the lighter block =

- friction force on the heavier block =

Let 'a' be the acceleration of the blocks and 'T' be the tension in the string.
From the f.b.d. of the lighter block,

From the f.b.d. of the heavier block,

From eqn (1) and (2), we get,

![\Rightarrow a\ =\ \dfrac{g(w_1sin\theta\ -\ \mu_1w_1cos\theta\ +\ w_2sin\theta\ +\ \mu_2w_2cos\theta)}{w_1\ +\ w_2}\\\Rightarrow a\ =\ \dfrac{g[sin\theta(w_1\ +\ w_2)\ +\ cos\theta(\mu_2w_2\ -\ \mu_1w_1)]}{w_1\ +\ w_2}\\](https://tex.z-dn.net/?f=%5CRightarrow%20a%5C%20%3D%5C%20%5Cdfrac%7Bg%28w_1sin%5Ctheta%5C%20-%5C%20%5Cmu_1w_1cos%5Ctheta%5C%20%2B%5C%20w_2sin%5Ctheta%5C%20%2B%5C%20%5Cmu_2w_2cos%5Ctheta%29%7D%7Bw_1%5C%20%2B%5C%20w_2%7D%5C%5C%5CRightarrow%20a%5C%20%3D%5C%20%5Cdfrac%7Bg%5Bsin%5Ctheta%28w_1%5C%20%2B%5C%20w_2%29%5C%20%2B%5C%20cos%5Ctheta%28%5Cmu_2w_2%5C%20-%5C%20%5Cmu_1w_1%29%5D%7D%7Bw_1%5C%20%2B%5C%20w_2%7D%5C%5C)
![\Rightarrow a\ =\ \dfrac{9.81\times [sin30^o\times (3.0\ +\ 7.0)\ +\ cos30^o\times (0.31\times 7.0\ -\ 0.13\times 3.0)]}{3.0\ +\ 7.0}\\\Rightarrow a\ =\ 6.4\ m/s.](https://tex.z-dn.net/?f=%5CRightarrow%20a%5C%20%3D%5C%20%5Cdfrac%7B9.81%5Ctimes%20%5Bsin30%5Eo%5Ctimes%20%283.0%5C%20%2B%5C%207.0%29%5C%20%2B%5C%20cos30%5Eo%5Ctimes%20%280.31%5Ctimes%207.0%5C%20-%5C%200.13%5Ctimes%203.0%29%5D%7D%7B3.0%5C%20%2B%5C%207.0%7D%5C%5C%5CRightarrow%20a%5C%20%3D%5C%206.4%5C%20m%2Fs.)
part (b)
From the eqn (2), we get,
Answer:
-360 kJ
Explanation:
Given:
m = 800 kg
v₀ = 30 m/s
v = 0 m/s
Δx = 75 m
Find: W
We can solve this using either forces or energy.
To use forces, first find the acceleration.
v² = v₀² + 2aΔx
(0 m/s)² = (30 m/s)² + 2a (75 m)
a = -6 m/s²
Then apply Newton's second law:
∑F = ma
F = (800 kg) (-6 m/s²)
F = -4800 N
Work is force times distance:
W = FΔx
W = (-4800 N) (75 m)
W = -360,000 J
W = -360 kJ
If you want to use energy instead:
work = change in energy
W = ΔKE
W = ½mv² − ½mv₀²
W = ½ (800 kg) (0 m/s)² − ½ (800 kg) (30 m/s)²
W = -360,000 J
W = -360 kJ
Explanation:
What is the weight of a 2.00-kilogram object on the surface of Earth?
2.00 N
4.91 N
9.81 N
19.6 N
Given parameters:
Mass of the object = 2kg
Unknown:
Weight of the object = ?
Solution:
The weight of an object is the force of gravity acting on the object;
Weight = mass x acceleration due to gravity
Acceleration due to gravity = 9.8m/s²
Now insert the parameters and solve;
Weight = 2 x 9.8 = 19.6N
A person weighing 785 Newtons on the surface of the Earth would weigh 47 Newtons on the surface of Pluto. What is the magnitude of the gravitational acceleration on the surface of Pluto?
1.7 m/s²
0.59 m/s²
0.29 m/s²
9.8 m/s²
Given parameters:
Weight on Earth = 785N
Weight on Pluto = 47N
Unknown:
Acceleration due to gravity on Pluto = ?
Solution
The mass of the body both on Earth and Pluto is the same.
Weight = mass x acceleration due to gravity
Now find the mass on Earth;
Acceleration due to gravity on Earth = 9.8m/s²
785 = mass x 9.8
mass =
= 80.1kg
So;
Acceleration due to gravity on Pluto =
Acceleration due to gravity =
= 0.59m/s²