Answer:
34.17°C
Explanation:
Given:
mass of metal block = 125 g
initial temperature
= 93.2°C
We know
..................(1)
Q= Quantity of heat
m = mass of the substance
c = specific heat capacity
c = 4.19 for H₂O in 
= change in temperature
Now
The heat lost by metal = The heat gained by the metal
Heat lost by metal = 
Heat gained by the water = 
thus, we have
= 

⇒ 
Therefore, the final temperature will be = 34.17°C
Answer:
Explanation:
We define the linear density of charge as:

Where L is the rod's length, in this case the semicircle's length L = πr
The potential created at the center by an differential element of charge is:

where k is the coulomb's constant
r is the distance from dq to center of the circle
Thus.

Potential at the center of the semicircle
Assuming 280 miles is the total distance travelled:
Let b = boat speed in still water
Let c = current speed.
For the downstream trip the speed is b + c. In 7 hours at the speed of (b + c) mph the boat travels 140 miles.
7(b + c) = 140 .............(1)
For the upstream trip the speed is b - c. In 14 hours at the speed of (b - c) mph the boat travels 140 miles.
14(b - c) = 140 ............(2)
The left hand sides of equations (1) and (2) are equal. Therefore we can write
7b + 7c = 14b - 14c ...........(3)
Rearranging equation (3) we get
21c = 7b
c = b/3 .......................(4)
The value for c obtained in equation (4) should now be substituted into equation (1) which can then be solved to find the value of b.
Answer:
Explanation:
Electric field due to charge at origin
= k Q / r²
k is a constant , Q is charge and r is distance
= 9 x 10⁹ x 5 x 10⁻⁶ / .5²
= 180 x 10³ N /C
In vector form
E₁ = 180 x 10³ j
Electric field due to q₂ charge
= 9 x 10⁹ x 3 x 10⁻⁶ /.5² + .8²
= 30.33 x 10³ N / C
It will have negative slope θ with x axis
Tan θ = .5 / √.5² + .8²
= .5 / .94
θ = 28°
E₂ = 30.33 x 10³ cos 28 i - 30.33 x 10³ sin28j
= 26.78 x 10³ i - 14.24 x 10³ j
Total electric field
E = E₁ + E₂
= 180 x 10³ j +26.78 x 10³ i - 14.24 x 10³ j
= 26.78 x 10³ i + 165.76 X 10³ j
magnitude
= √(26.78² + 165.76² ) x 10³ N /C
= 167.8 x 10³ N / C .