Answer:
60 J
Explanation:
Potential Energy: This can be defined as the energy possessed by a body, due to its position. The S.I unit of potential energy is Joules. The Formula of potential energy is given as
Ep = mgh or
Ep = Wh ................ Equation 1
Where Ep = Potential energy of the box, W = Weight of the box, h = Height.
Given: W = 20 N, h = 3 m.
Substitute into equation 1
Ep = 20×3
Ep = 60 J.
Hence the gravitational potential energy of the box = 60 J
Answer:
F = 3.6 10⁶ N
Explanation:
The expression for the electric force is
F = ![k \ \frac{q_1 q_2}{r^2}](https://tex.z-dn.net/?f=k%20%5C%20%5Cfrac%7Bq_1%20q_2%7D%7Br%5E2%7D)
in this case it indicates that the charge q1 is doubled
q₁ = 2 3 10⁻³ C
q₁ = 6 10⁻³ C
let's reduce the magnitudes to the SI system
q₂ = 6 10⁻³ C
r = 0.3 m
let's calculate
F = 9 10⁹ 6 10⁻³ 6 10⁻³ / 0.3²
F = 3.6 10⁶ N
3. An object will float if its density is less than the matter it is submerged in.
If it sinks in water, its density is more than 1. If it floats in glycerin, its density is less than 1.26.
Answer:
4.11 s.
Explanation:
The period T of oscillation of the pendulum is given by the formula:
![T = 2 \pi * \sqrt{\frac{L}{g} }](https://tex.z-dn.net/?f=T%20%3D%202%20%5Cpi%20%2A%20%5Csqrt%7B%5Cfrac%7BL%7D%7Bg%7D%20%7D)
The maximum oscillation point it can reach is 45 °,
This point is the equivalent of T / 4, which is the moment when it reaches equilibrium.
So for T / 4,
![T = 2\pi * \sqrt{l / g} = 2 \pi \sqrt{(67 / 9.81)} = 16.42](https://tex.z-dn.net/?f=T%20%3D%202%5Cpi%20%2A%20%5Csqrt%7Bl%20%2F%20g%7D%20%3D%202%20%5Cpi%20%5Csqrt%7B%2867%20%2F%209.81%29%7D%20%3D%2016.42)
![t = T / 4 = 16.42 / 4 = 4.11 s](https://tex.z-dn.net/?f=t%20%3D%20T%20%2F%204%20%3D%2016.42%20%2F%204%20%3D%204.11%20s)
Answer:
Angle with the +x axis is θ = 79.599degree
Then the velocity of owner = 1.235m/s
Explanation:
Given that the mass of dog is m1 =26.2 kg
velocity of dog is u1 = 3.02 m/s (north)
mass of cat is m2 = 5.3 kg
velocity is u2 = 2.74 m/s (east )
Mass of owner is M = 65.1 kg
Consider the east direction along +x axis andnorth along +y
momentum of dog is Py = m1 x u1
= 79.124 kg.m/s (j)
momentum of cat is Px = m2 x u2
= 14.522 kg.m/s (i)
Then the net magnitude of momentum is P = (Px2 + Py2)1/2
= 80.445
Angle with the +x axis is θ =tan-1(Py / Px ) = 79.599 degree
Then the velocity of owner is v = P / M = 1.235 m/s