A ball rolls onto the path of your car as you drive down a quiet neighborhood street. To avoid hitting the child that runs to re
1 answer:
Answer:
F = 7.143 kN
Explanation:
given,
time taken to apply break = 1.05 s
car slows down from 15 m/s to 9 m/s
mass of the car = 1250 Kg
force is equal to the change in momentum with respect to time.
F = -7142.85 N
F = - 7.143 kN
Force is acting opposite direction of velocity of car i.e. the sign is negative.
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Answer : The rate of heat transfer to the water is, 37.92 kJ/min
Explanation : Given,
Time = 10 min
Mass of water = 200 g
Latent heat of fusion of water = 334 J/g
Latent heat of vaporization of water = 2230 J/g
Now we have to calculate the rate of heat transfer to the water.
Now put all the given values in the above formula, we get:
Thus, the rate of heat transfer to the water is, 37.92 kJ/min
Answer:
The expression for the initial speed of the fired projectile is:
And the initial speed ratio for the 9.0mm/44-caliber bullet is 1.773.
Explanation:
For the expression for the initial speed of the projectile, we can separate the problem in two phases. The first one is the moment before and after the impact. The second phase is the rising of the ballistic pendulum.
First Phase: Impact
In the process of the impact, the net external forces acting in the system bullet-pendulum are null. Therefore the linear momentum remains even (Conservation of linear momentum). This means:
(1)
Second Phase: pendular movement
After the impact, there isn't any non-conservative force doing work in al the process. Therefore the mechanical energy remains constant (Conservation Of Mechanical Energy). Therefore:
(2)
The height of the pendulum respect L and θ is:
(3)
Using equations (1),(2) and (3):
(4)
The initial speed ratio for the 9.0mm/44-caliber bullet is obtained using equation (4):