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2 years ago

A crash test dummy is inside a test car moving at 55 km/h. How fast is the dummy moving relative to the seat he is sitting in?

2 answers:

8 0

The situation is exactly the same as YOUR speed relative to the seat you're sitting in, aboard the passenger jet flying at 500 mph with you in it.

kvasek [131]2 years ago

7 0

The dummy is moving with a speed 0 km/h relative to the seat in which it is sitting.

If the relative speed was non-zero, the dummy would move away from its seat, which contradicts the problem formulation.

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The greatest height reported for a jump into an airbag is 99.4 m by stuntman Dan Koko. In 1948 he jumped from rest from the top

leva [86]

Answer:

44.1613858478 m/s

Explanation:

t = Time taken

u = Initial velocity = 0

v = Final velocity

s = Displacement = 99.4

a = Acceleration

g = Acceleration due to gravity = 9.81 m/s² = a

$v^2-u^2=2as\\\Rightarrow v=\sqrt{2as+u^2}\\\Rightarrow v=\sqrt{2\times 9.81\times 99.4+0^2}\\\Rightarrow v=44.1613858478\ m/s$

If air resistance was absent Dan Koko would strike the airbag at 44.1613858478 m/s

6 0

2 years ago

How did Albert Einstein come up with 3 = mc square pls help

inysia [295]

Answer: He came up with this by using theories like the photoelectric effect, the second offered experimental proof of the existence of atoms, and the third introduced the theory of special relativity.

Explanation: He was explaing the realationship between energy and mass.

Me: Hope this helps!!! May I have brainlist!?

4 0

2 years ago

All electromagnetic waves travel in vacuum at the speed of c=3×10^8 m/s. Find the wavelength of microwaves of frequency 10^10 Hz

erica [24]

Recall the wave equation, $c=f\lambda$ where c is the speed of the wave (m/s), f is the frequency of the wave (Hz) and λ is the wavelength of the wave (m).

$c=f\lambda \Rightarrow \lambda = \frac{c}{f}$ so $\lambda = \frac{3 \times 10^8}{10^{10}} = 0.03 \text{m}$

5 0

2 years ago

A 55 kilogram person jumps off a cliff and hits the water 5.8 seconds later, how high is the cliff above the water?

ElenaW [278]

R=ut+gt^2/2
r- displacement (height to find)
u - initial speed (zero)
t - time taken

r=0*5.8 + 10*5.8^2 /2 = 168.2 meters

8 0

2 years ago

A child is holding a wagon from rolling straight back down in a driveway that inclined at 20 degree horizontal. if the wagon wei

Alenkinab [10]

Answer:

F = 51.3°

Explanation:

The component of weight parallel to the inclined plane must be responsible for the rolling back motion of the car. Hence, the force required to be applied by the child must also be equal to that component of weight:

$F = Parallel\ Component\ of\ Weight\ of\ Wagon= WSin\theta\\$

where,

W = Weight of Wagon = 150 N

θ = Angle of Inclinition = 20°

Therefore,

$F = (150\ N)Sin\ 20^o$

8 0

2 years ago