Room heaters are placed on the floor of a room so that the air heated by it rises up and sets up the convection current in the room quickly and uniformly.
Answer:
238.75⁰C .
Explanation:
coefficient of linear thermal expansion of aluminum and steel is 23 x 10⁻⁶ K⁻¹ and 12 x 10⁻⁶ K⁻¹ respectively .
Rise in temperature be Δ t .
Formula for linear expansion due to heat is as follows
l = l₀ ( 1 + α x Δt )
l is expanded length , l₀ is initial length , α is coefficient of linear expansion and Δt is increase in temperature .
For aluminum
l = 2.5 ( 1 + 23 x 10⁻⁶ Δt )
For steel
l = 2.506 ( 1 + 12 x 10⁻⁶ Δt )
Given ,
2.5 ( 1 + 23 x 10⁻⁶ Δt ) = 2.506 ( 1 + 12 x 10⁻⁶ Δt )
1 + 23 x 10⁻⁶ Δt = 1.0024 ( 1 + 12 x 10⁻⁶ Δt )
1 + 23 x 10⁻⁶ Δt = 1.0024 + 12.0288 x 10⁻⁶ Δt
10.9712 x 10⁻⁶ Δt = .0024
Δt = 218.75
Initial temperature = 20⁰C
final temperature = 218.75 + 20 = 238.75⁰C .
Answer:
This is about 176 times the weight of the froghopper.
Explanation:
the grasshopper converts kinetic energy into earth gravitational potential energy
u=mgh
u=12*10^-3*9.8*0.7
=8.23*10^-2
using the Work energy principle
equating the kinetic energy to the potential energy
k +U+w=K2+u2
K+0+0=0+U2
k=8.23*10^-2
force exerted by the grasshopper on the round will be given by tis equation
(F-mg)Ycos
=k
(F-12*10^-3*9.8)*0.004cos 0=8.23*10^-2
F=20.7N
from newtons third law of motion, action and reaction are equal and opposite
F=-20.7N
comparing the forces by the two bodies
F:mg
-20.7:-12*10^-3*9.8
the magnitude of the force applied by the grasshopper is found to be 176 times the gravitational force
Good conductors are the materials which allow electricity to pass through them easily whereas, bad conductors are the materials which do not allow electricity to pass through them. Good conductors offer less resistance to the flow of current, whereas the bad conductors do not transmit current through them.
The question isn't clear enough, I think it ask us to calculate the linear speed of a point at the edge of the DVD.
Now let's imagine we're a point at the edge of the DVD, we're undergoing a circular motion. Each minute we will complete a circular track 7200 times, now we need to know the distance we travel each turn. The perimeter of the DVD, a circular object is:

Know recall that:

We now need to know how much distance is traveled during a minute or 60 seconds:

Finally we divide this result with t=60 seconds:


Where the distance units were named units as the length unit is not specified in this exercise.<span />