Answer:
7.5Watts
Explanation:
Given parameters:
Force of lift = 25N
Height = 3.6m
Time = 12s
Unknown:
Power output = ?
Solution:
Power is the rate at which work is done ;
Power =
Power =
= 7.5Watts
Answer:
The average speed for the entire run is 12 km/h.
Explanation:
The average speed is given by the following equation:

Where:
: is the total distance
: is the total time
If during the first hour, they ran a total of 13 kilometers and then, they ran 5.0 kilometers during the next half an hour we have:


Hence, the average speed is:

Therefore, the average speed for the entire run is 12 km/h.
I hope it helps you!
Answer:
The Mass of a person is calculated to be 28.6kg .
Explanation:
This is based on Kinetic energy and we know, that Kinetic energy is the energy possessed by body by virtue of its motion .
It can be calculated by expression :
K.E=1/2mv²
Velocity of a person = 11.2m/sec
Kinetic energy = 1800J
Mass of person = ?
We know ,
K.E=1/2mv²
so, putting values we have :
1800=1/2 x m x (11.2)²
That is ,
m=1800 x 2 /11.2 x 11.2
or
m=3600/125.44
m = 28.6 kg
To find this we should use the equation Ek=1/2mv^2 where Ek is the kinetic energy, m is the mass and v is the velocity. So by this Ek=1/2*1*30^2 which then makes Ek=450 joules
Answer: B. The copper wire (resistance 0.1)
Explanation: When resistance is in parallel, voltage (V) is the same but current is different for every resistance. Current (i) is related to voltage and resistance (R) by <em>Ohm's Law</em>
i =
So, since both wires are in parallel, they have the same voltage but because the copper wire resistance is smaller than Nichrome wire, the first's current will be bigger.
Every resistor in a circuit dissipates electrical power (P) that is converted into heat energy. The dissipation can be found by:
P = 
As current for copper wire is bigger than nichrome, power will be bigger and it will dissipate more heat.
In conclusion, the copper wire will dissipate more heat when connected in parallel.