Answer:
B) the change in momentum.
Explanation:
The impulse is defined as the product between the force applied on an object (F) and the duration of the collision (
):
(1)
We can rewrite the force by using Newton's second law, as the product between mass (m) and acceleration (a):
So, (1) becomes
Now we can also rewrite the acceleration as ratio between the change in velocity and change in time: 
. If we substitute into the previous equation, we find
And the quantity 
is equivalent to the change in momentum, 
.
If 56.5kJ are needed to raise the temp by 90°C and if the heater is 60% efficient that means that:
60% X y = 56.5kJ
where y is the electrical energy in kJ that the heater will use.
y = 94.2kJ
Answer:
2513.6 W
Explanation:
Acoustic power = sound intensity × area of hemisphere
Sound intensity = 1 W/m^2
Area of hemisphere = 2πr^2 = 2×3.142×20^2 = 2513.6 m^2
Acoustic power = 1 W/m^2 × 2513.6 m^2 = 2513.6 W
Answer:
250 m
Explanation:
The car in this problem is moving of uniform accelerated motion, so we can use the following suvat equation:
where
s is the distance covered
u is the initial velocity
t is the time
a is the acceleration
Assuming the car starts from rest,
u = 0
Also we know that
a = 5 m/s^2 (acceleration of the car)
t = 10 s
Substituting, we find the distance covered:
