The answer is D. Electric resistance increases with an increase in the length of a wire and as a result current flow decreases. There is a direct relationship between the length of the wire and the resistance. The longer the wire, the more resistance there will be. Additionally, from Ohm's Law, current is inversely proportional to resistance. This means as the current increases, resistance decreases or vice versa.
<h3>
Answer:</h3>
49 N
<h3>
Explanation:</h3>
<u>We are given;</u>
- Mass of the brick as 3 kg
- The coefficient of friction as 0.6
We are required to determine the force that must be applied by the woman so the brick does not fall.
- We need to importantly note that;
- For the brick not to fall the, the force due to gravity is equal to the friction force acting on the brick.
- That is; Friction force = Mg
But; Friction force = μ F
Therefore;
μ F = mg
0.6 F = 3 × 9.8
0.6 F = 29.4
F = 49 N
Therefore, she must use a force of 49 N
Answer:
t=40s,
Explanation:
If you can swim in still water at 0.5m/s, the shortest time it would take you to swim from bank to bank across a 20m wide river, if the water flows downstream at a rate of 1.5m/s, is most nearly:
from the question the swimmer will have a velocity which is equal to the sum of the speed of the water and the velocity to swi across the bank
Vt=v1+v2
the time is takes to swim across the bank will be
DY=Dv*t
DY=distance across the bank
Dv=ther velocity of the swimmer across the bank
t=20/ 0.5m/s,
t=40s, time it takes to swim across the bank
velocity is the rate of displacement
displacement is distance covered in a specific direction
The specific heat of a metal or any element or compound can be determined using the formula Cp = delta H / delta T / mass. delta pertains to change. That is change in enthalpy and change in temperature. From the given data, Cp is equal to 343 cal per (86-19) c per 55 grams. This is equal to 0.093 cal / g deg. Celsius
Answer:
69.69 g
Explanation:
Evaporation of water will take out latent heat of vaporization. Let the mass of water be m and latent heat of vaporization of water be 2260000 J per kg
Heat taken up by evaporating water
= 2260000 x m J
Heat lost by body
= mass x specific heat of body x drop in temperature
60 x 3500 x .750 ( specific heat of human body is 3.5 kJ/kg.k)
= 157500 J
Heat loss = heat gain
2260000 m= 157500
m = .06969 kg
= 69.69 g
