E=Eq,
where F is the electrostatic force (or Coulomb force) exerted on a positive test charge q.
Answer:
a) a = 6.1 m/s^2
b) a = 0.98m/s^2
Explanation:
Mass of slab = 40kg
Mass of block = 10kg
Coefficient of static friction (Us) = 0.60
Kinetic coefficient (UK) = 0.40
Horizontal force = 100N
The normal reaction from 40kg slab on 10 kg block = 10*9.81
= 98.1N
Static frictional force = Us*R
= 98.1*0.6
= 58.86N
This is less than the force applied
If 10 kg block will slide on the 40 kg slab, net force = 100 - kinetic force
Kinetic force (Uk*R) = 0.4*98.1
= 39.28N
= 39N
Net force = 100 -39
= 61N
Recall that F = ma
For 10 kg block
a = F/m
a = 61/10
a = 6.1m/s^2
b) Frictional force on 40 kg slab by 10 kg = 98.1*0.4
= 39.24
= 39N
F = ma
a = F/m
For 40kg slab
a = 39/40
a = 0.98m/s^2
Answer:
The thermal energy is carried by electromagnetic waves
Explanation:
There are three types of transfer of heat (thermal energy):
- Conduction: conduction occurs when two objects/two substances are in contact with each other. The heat is transferred from the hotter object to the colder object by the collisions between the molecules of the two mediums.
- Convection: convection occurs when a fluid is heated by an external source of heat. The part of the fluid closer to the heat source gets warmer, therefore it becomes less dense and it rises, and it is replaced by the colder part of the fluid, which is colder. Then, this part of fluid is heated as well, so it gets warmer, it rises, etc.. in a cycle.
- Radiation: radiation occurs when thermal energy is carried by electromagnetic waves. Since electromagnetic waves do not need a medium to propagate, this is the only method of heat transfer that can occur through a vacuum (so, in space as well).
Indeed, the Sun emits a lot of electromagnetic radiation, which travels through space and eventually reaches the Earth, heating it.
Answer:
The time taken to rotate the sphere one time is, t = 22 s
Explanation:
Given data,
The mass of the sphere, m = 8200 kg
The radius of the sphere, r = 90 cm
= .9 m
The force applied by the girl, F = 75 N
The moment of inertia of the sphere is,
I = 2/5 mr²
= (2/5) 8200 x (.9)²
= 2657 kg·m²
The torque,
τ = I α
75 x 0.9 = 2657 x α
α = 0.0254 rad/s²
The angular displacement,
θ = ½αt²
2π = ½ x 0.0254 rad/s² x t²
t = 22 s
Hence, the time taken to rotate the sphere one time is, t = 22 s
Answer:
Momentum is conserved in all three physical directions at the same time.
Explanation:
There is a peculiarity, however, in that momentum is a vector, involving both the direction and the magnitude of motion, so that the momenta of objects going in opposite directions can cancel to yield an overall sum of zero.
