Natural gas, nuclear reactions, wind, water
Explanation:
in my opinion I'd say it's gravity because it's making the book stay in it's one and only position pulling the book at the center of the desk
Answer:
b
Explanation:
n = m(g +a)
n= normal force (N)
m=mass (kg)
g=acceleration of gravity
a= acceleration of elevator
rearrange:
a= n/m - g
a= (810 N/73 kg) - 9.8 m/s ^2
a= 1.3 m/s ^2 up
and the acceleration is upwards bc her weight is less than the scale reading
Answer:
c) is negative
Explanation:
As we know that work done by a force is the product of force and displacement vector.
W= F.d
F= Force
d= displacement
The work done by friction force always negative because it try to oppose the motion and act opposite to the direction of displacement.So the work done by air resistance is negative.
c) is negative
Answer:
She is not getting a good deal.
Explanation:
The equation that relates heat with mass, specific heat and temperature change of an object is 
.
Always convert temperature to Kelvin, although in our case it's not necessary because the 
will be the same, and we will leave the mass in grams because we will be getting 
units for specific heat, which we can compare to the one given for gold.
We then calculate the specific heat of the object in question:
Which shows it's not gold.
