6.
Basically, all of these questions use F = ma
m = 80 kg
a = 1.62
Weight = F = 80*1.62 = 129.6
The closest answer is B
7.
<em><u>Step One</u></em>
Find the mass here on earth
m = F/a
F = 40 kg
a = 9.2
F = 40/9.2 = 4.34
Now take everything to the moon
F = 20 kg
a = ??
m = 4.34
a = F/m = 20/4.34 = 4.6 m/s^2
8
m = 40 kg
F = 20 N
a = ??
a = F/m = 20N/40kg = 1/2 m/s^2
Comment
All of these depend on F = m*a. None but the first one talk about vertical forces where gravity would play a part. Moving horizontally means that there is no gravitational force if there is no friction. a = 9.8 has nothing to do with the problem.
Answer:
0.061 J
Explanation:
The kinetic energy of an object is given by
where
m is the mass of the object
v is its speed
For the toy truck in the problem, we have
m = 0.1 kg is its mass
v = 1.1 m/s is its speed
Putting the numbers into the equation, we find
Physical properties do not change the chemical nature of matter.
They are things you can observe and touch.
Answer:
46.19 L
Explanation:
The efficiency of the solar water heater is 40% which means 40% of the solar energy is converted to useful energy, ie. used to heat the water.
Useful energy = P = solar energy * available area * efficiency
P = 200 W/m^2 * 29.5 m^2 * 40%
P = 2360 W = 2.36 kJ/s
This means that 2.36 kJ of useful energy will be utilized per second. Converting this to the useful energy in hour gives us:
Average energy in one hour = 2.36 kJ/s * 3600 s/h = 8496 kJ
The specific heat capacity of water is 4.18 kJ/kg.C which means it will take 4.18 kJ of energy to raise the temperature of 1 kg of water by 1 degree C. Equating the energy change of the water for the given temperature rise and mass (unknown) to the useful energy utilized in one hour, we can solve to determine the unknown mass. This will give us the mass of water heated in one hour:
Energy = mass * specific heat capacity * (final temperature - initial temperature)
8496 = mass * 4.18 * (60 - 16)
mass = 46.19 kg
Lastly, this mass has to be converted to volume. Assuming density of water is constant through out the heating process:
volume = mass / density
volume = 46.19 kg / 1 kg/L
volume = 46.19 L
Explanation:
Contact force is any force that requires contact. An object that exerts a force on another object by touching it is exerting a contact force. Examples of contact force are friction and normal force.
Examples of a non-contact force are gravity and magnetism.
