Final answer:
The average force experienced by your cousin is 4500 N, and the force experienced by the tree is also 4500 N. This force can be expressed as approximately 1012 pounds. Your cousin experienced an acceleration of approximately -9 g's.
Step-by-step explanation:
The average force experienced by your cousin can be calculated using Newton's second law, which states that force is equal to mass multiplied by acceleration.
In this case, the mass of your cousin and the car is 450 kg, and the change in velocity is from 36 km/hr to 0 km/hr in 0.40 seconds. To calculate the acceleration, we need to convert the change in velocity from km/hr to m/s.
Multiplying 36 km/hr by the conversion factor (1000/3600) gives us an acceleration of 10 m/s2.
Now, we can use the formula F = ma to find the force. Substituting the values,
we have F = 450 kg * 10 m/s2
= 4500 N.
The average force experienced by the tree can be determined using Newton's third law, which states that for every action, there is an equal and opposite reaction.
Since the force exerted by your cousin on the tree is 4500 N, the force exerted by the tree on your cousin is also 4500 N.
To express this force in pounds, we can use the conversion factor of 1 N = 0.2248 pounds.
So, the average force experienced by your cousin and the tree is (4500*0.2248)= approximately 1012 pounds.
To calculate the acceleration experienced by your cousin, we can use the formula a = Δv / t, where Δv is the change in velocity and t is the time taken.
Substituting the values, we have a = (0 - 36 km/hr) / (0.40 s)
= -90 m/s2.
The acceleration can also be expressed in terms of g's, where 1 g is equal to approximately 9.8 m/s2.
Dividing -90 m/s2 by 9.8 m/s2/g, we find that your cousin experienced an acceleration of approximately -9 g's.