1.
Answer:
Part a)

Part b)

Explanation:
Part a)
Length of the rod is 1.60 m
diameter = 0.550 cm
now if the current in the ammeter is given as

V = 17.0 volts
now we will have


R = 0.91 ohm
now we know that



Part b)
Now at higher temperature we have


R = 0.98 ohm
now we know that



so we will have



2.
Answer:
Part a)

Part b)

Explanation:
Part a)
As we know that current density is defined as

now we have

Now we have


so we will have

Part b)
now we have

so we have


so we have


Answer:
a

b

Explanation:
From the question we are told that
The mass of the rock is 
The length of the small object from the rock is 
The length of the small object from the branch 
An image representing this lever set-up is shown on the first uploaded image
Here the small object acts as a fulcrum
The force exerted by the weight of the rock is mathematically evaluated as

substituting values


So at equilibrium the sum of the moment about the fulcrum is mathematically represented as

Here
is very small so
and 
Hence

=> 
substituting values


The mechanical advantage is mathematically evaluated as

substituting values


Answer:
B. 2 meters.
Explanation:
To rotate the capstan a certain amount of torque is required, and if each sailor applies a force
at a distance
from the center, then for two sailors the total torque will be
;
therefore, for one sailor to apply the same torque it must be that the torque
he applies must be equal to the torque that the two sailors applied:

which gives
.
and since
,

which is choice B.
<u>Out of the given options, the following interactions are part of the greenhouse effect,
</u>
- Gases in the atmosphere absorb heat
- Earth’s surface radiates energy back into the atmosphere
- Gases in the atmosphere radiate heat back to the surface
Answers: Options A, D and E
<u>Explanation:
</u>
The greenhouse effect, basically a warming effect caused by the greenhouse gases such as Carbon-Di-oxide, Methane, nitrous oxides, water vapour etc. These gases usually trap the heat that Earth Absorbs by the Sun.
In the day time, the Earth absorbs the energy in the form of heat which is radiated by the Sun. In the evening, the process gets reversed and the Earth starts releasing that heat into the atmosphere.
Now, this heat gets absorbed by this gases before it leaves the Earth's atmosphere and gets trapped there only, resulting in the temperature raise of the Earth's environment.
So, the prime causes of the greenhouse effect remains as the heat radiation from the Sun, the absorption of that heat by the Earth surface and the further absorption of that heat produced by the greenhouse gases that present in the atmosphere.
<h2><u>We have</u>,</h2>
- Initial velocity (u) = 0 m/s
- Time taken (t) = 2.9s
- Acceleration due to gravity (g) = + 10 m/s² [Down]
<h2><u>To calculate</u>,</h2>
- Final velocity (v)
- Height (h)
<h2><u>Solution</u><u>,</u></h2>
→ v = u + gt
→ v = 0 + 10(2.9)
→ v = 29 m/s
… ( Ans )
And,
→ h = ut + ½gt²
→ h = 0(2.9) + ½ × 10 × (2.9)²
→ h = 5 × 8.41
→ h = 42.05 m
… ( Ans )