In a car crash, large accelerations of the head can lead to severe injuries or even death. A driver can probably survive an acce
1 answer:
Answer:
0.22 m
Explanation:
We are told that the driver can survive an acceleration of 50g only if the collision lasts no longer than 30 ms. So,
The acceleration is
where the negative sign is due to the fact that this is a deceleration, since the driver comes to a stop in the collision.
First of all, we can find what the initial velocity of the car should be in this conditions by using the equation:
And since the final velocity is zero, v=0, and solving for u,
And now we can find the corresponding distance travelled using the equation:
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Answer:
a) 1.2*10^-7 m
b) 1.0*10^-7 m
c) 9.7*10^-8 m
d) ultraviolet region
Explanation:
To find the different wavelengths you use the following formula:
RH: Rydberg constant = 1.097 x 10^7 m^−1.
(a) n=2
(b)
(c)
(d) The three lines belong to the ultraviolet region.
Answer:
1. False 2) greater than. 3) less than 4) less than
Explanation:
1)
- As the collision is perfectly elastic, kinetic energy must be conserved.
- The expression for the final velocity of the mass m₁, for a perfectly elastic collision, is as follows:
- As it can be seen, as m₁ ≠ m₂, v₁f ≠ 0.
2)
- As total momentum must be conserved, we can see that as m₂ > m₁, from the equation above the final momentum of m₁ has an opposite sign to the initial one, so the momentum of m₂ must be greater than the initial momentum of m₁, to keep both sides of the equation balanced.
3)
- The maximum energy stored in the in the spring is given by the following expression:
- where A = maximum compression of the spring.
- This energy is always the sum of the elastic potential energy and the kinetic energy of the mass (in absence of friction).
- When the spring is in a relaxed state, the speed of the mass is maximum, so, its kinetic energy is maximum too.
- Just prior to compress the spring, this kinetic energy is the kinetic energy of m₂, immediately after the collision.
- As total kinetic energy must be conserved, the following condition must be met:
- So, it is clear that KE₂f < KE₁₀
- Therefore, the maximum energy stored in the spring is less than the initial energy in m₁.
4)
- As explained above, if total kinetic energy must be conserved:
- So as kinetic energy is always positive, KEf₂ < KE₁₀.
Answer:
The gplanet is 0.193 m/s^2
Explanation:
The speed of the pulse is:
where
m=mass of the wire=4 g= 4x10^-3 kg
M=mass of the object= 3 kg
Replacing values: