Answer:
The mass of the child + skateboard is 50 kg
Explanation:
In this problem, we can apply Newton's second law:
F = ma
where
F is the net force on a system
m is the mass of the system
a is the acceleration of the system
In this problem, our system is the child + the skateboard. The net force on them is
F = 75 N
and their acceleration is

So we can re-arrange the equation above to find their combined mass:

Answer:
A - Crest, B - amplitude, C - wavelength, D - trough
Explanation:
gawaingnpang nkabuhayan, hamon at oportinidad
mass gram, time sec, temp kelvin, vol liter, dens grams/cm3
Friction occurs when the surfaces and heat of two surfaces grind against each other.
I think these are the answers