Answer:
1) joule
2) 
3) 
Explanation:
1) Luminosity is the <u>amount of light emitted</u> (measured in Joule) by an object in a unit of<u> time</u> (measured in seconds). Hence in SI units luminosity is expressed as joules per second (
), which is equal to Watts (
).
This amount of light emitted is also called radiated electromagnetic power, and when this is measured in relation with time, the result is also called radiant power emitted by a light-emitting object.
Therefore, if we want to calculate luminosity the Joule as a unit will be used.
2) Work
is expressed as force
multiplied by the distane
:
Where force has units of
and distance units of
.
If we input the units we will have:
This is 1Joule (
) in the SI system, which is also equal to 
3) The formula to calculate the percent error is:

Where:
is the experimental value
is the accepted value

This is the percent error
The mass of the second car is 1434.21 kg
<u>Explanation:</u>
Using law of conservation of momentum,

Given:
= 1090 kg
= 11 m/s
= 0
v = 4.75 m/s
We need to find 
When substituting the given values in the above equation, we get





Answer:
D. Metallic atoms have valence shells that are mostly empty, which
means these atoms are more likely to give up electrons and allow
them to move freely.
Explanation:
Metals usually contain very few electrons in their valence shells hence they easily give up these few valence electrons to yield metal cations.
In the metallic bond, metal cations are held together by electrostatic attraction between the metal ions and a sea of mobile electrons.
Since metals give up their electrons easily, it is very easy for them to participate in metallic bonding. They give up their electrons easily because their valence shells are mostly empty, metal valence shells usually contain only a few electrons.
Answer:
The distance travelled on the freeway is 149.5 miles.
Explanation:
The school bus travels on the freeway at constant speed. According to the statement, we need to calculate the distance travelled by the vehicle by means of the following formula:
(1)
Where:
- Traveled distance, in miles.
- Speed, in miles per hour.
- Time, in hours.
If we know that
and
, then the distance travelled by the school bus is:



The distance travelled on the freeway is 149.5 miles.