I believe the answer is a: cells.
Answer:
1) The block of wood is at rest.
2) Weight and Normal Reaction (see attached diagram).
Explanation:
<u>Assumptions</u>
- The block of wood is a particle (a body whose mass acts at a point, so its dimensions don't matter).
- There are no other external forces involved.
<u>Question 1</u>
"At rest" or "resting" means that the <u>object isn't moving</u>.
Therefore, the block of wood is at rest.
<u>Question 2</u>
Forces that are acting on the block of wood:
- <u>Weight (W)</u>: Due to the particle's mass, m, and the acceleration due to gravity, g: W = mg
(Weight always acts downwards).
- <u>Normal Reaction (R or N)</u>: The reaction from a surface.
(Normal Reaction is always at 90° to the surface).
See attached diagram.
Answer:
All are not true.
Explanation:
Sound needs medium to travel.
sound speed is fastest in solids.
Answer:
The current in the rods is 171.26 A.
Explanation:
Given that,
Length of rod = 0.85 m
Mass of rod = 0.073 kg
Distance
The rods carry the same current in the same direction.
We need to calculate the current
I is the current through each of the wires then the force per unit length on each of them is
Using formula of force
Where, m = mass of rod
l = length of rod
Put the value into the formula
Hence, The current in the rods is 171.26 A.
Answer:
Explanation:
For resistance of a wire , the formula is as follows .
R = ρ L/S
where ρ is specific resistance , L is length and S is cross sectional area of wire .
for first wire resistance
R₁ = ρ 3L/3a = ρ L/a
for second wire , resistance
R₂ = ρ 3L/6a
= .5 ρ L/a
For 3 rd wire resistance
R₃ = ρ 6L/3a
= 2ρ L/a
For fourth wire , resistance
R₄ = ρ 6L/6a
= ρ L/a
So the smallest resistance is of second wire .
Its resistance is .5 ρ L/a