Answer:
the answer is A.
Explanation:
Using the laws of newton:
∑F = ma
where ∑F is the sumatory of forces acting in the system, m the mass and a the acelertion of the system.
Then, if the block is moving with constant velocity, its aceleration is equal to 0, so:
∑F = m(0)
∑F = 0
It means that:
F -
= 0
where F is the force applied and is the friction force. Replacing the value of F, we get:
310N - = 0
Finally, solving for :
Answer:
T=280.41 °C
Explanation:
Given that
At T= 24°C Resistance =Ro
Lets take at temperature T resistance is 2Ro
We know that resistance R given as
R= Ro(1+αΔT)
R-Ro=Ro αΔT
For copper wire
α(coefficient of Resistance) = 3.9 x 10⁻³ /°C
Given that at temperature T
R= 2Ro
Now by putting the values
R-Ro=Ro αΔT
2Ro-Ro=Ro αΔT
1 = αΔT
1 = 3.9 x 10⁻³ x ΔT
ΔT = 256.41 °C
T- 24 = 256.41 °C
T=280.41 °C
So the final temperature is 280.41 °C.
Answer:
Explanation:
Given two mass on an incline code 
and 
and an angle of inclination 
. 
. Assume that is the weight being pulled up and the hanging weight.
-The equations of motion from Newton's Second Law are:
where a is the acceleration.
#Substituting for 
(tension) gives:
#and solving for 
which is the system's acceleration.
Answer: B. meteorites, UV rays
The earth's atmosphere plays an important role in shielding the space rocks and meteorites enters inside the earth due to collision with the celestial body. Due to high heat and pressure in the mesospheric layer of the atmosphere these meteorites burned up before reaching the biosphere or hydrosphere system of the earth. The UV rays are protected from entering into the earth atmosphere by the ozone layer present in the stratosphere of the atmosphere. Both meteorites and UV rays can negatively effect the human population. Therefore, the atmosphere is an agent which provides protection against them.
