Momentum = mass × velocity
360 = mass × 7.2
mass = 360/7.2 = 50 kg
Hope it helped!!
Not sure what your question means but the nearest star is Alpha Centauri which is about 4.2 light years (ly) away. This is roughly 4x10¹³ km away. A billion is 10⁹ so this is 4x10⁴ larger than a billion. I'd say the last one then...
Answer:
There will be a phase change at the first interface and no phase change at the second interface:
If the film is 1/4 wavelength thick this restriction will hold
The wavelength of the light in oil is 545 nm / 1.45 = 376 nm
376 nm / 4 = 94 nm
"D" is correct
Answer:
Explanation:
Remark
This is a second class lever. It is much more efficient than the fishing pole problem. All distances are measured from the pivot in these kinds of questions.
Givens
d1 = 1.5
d2 = ?
m1 = 50 kg
m2 = 30 kg
The lighter child will have to sit further away from the pivot to make the two conditions equal.
Formula
d1*m1 = d2*m2
1.5*50 = d2 * 30
75 = 30 * d2
75/30 = d2
d2 = 2.5
Remark
Notice that the distance is longer for the lighter child. The fact that these are masses and not forces does not matter, but you should take note of it. There is a difference between masses and forces. See the fishing pole problem.
Answer to the multiple Choice question. No motion on this kind of problem means equal moments. The answer is D
Problem 2
1) The wheels are further apart making B more stable. The wider the distance the wheels are apart, the harder it would be to tip the concrete mixer over
2) The center of gravity is lower. The higher the force is the more chance you have of exerting an external force to tip the mixer over.
Because they are. it’s just how life works
