Answer:
8000J
Explanation:
The kinetic energy of the car lost during breaking are converted to thermal energy and are gained by the brakes.
Kinetic energy loss by car = thermal energy gained by brakes.
∆K.E = ∆T.E ....1
The Kinetic energy loss by car can be expressed as;
∆K.E = K.E1 - K.E2
Initial K.E = K.E1 = 10000J
Final K.E = K.E2 = 2000J
∆K.E= 10000J - 2000J = 8000J
From equation 1,
∆K.E = ∆T.E
∆T.E = 8,000J
thermal energy gain by brakes = 8,000J
Answer: My initial velocity is 5 m/s.
Explanation:
In this case, momentum can be conserved.
initial momentum = final momentum
Since both the bodies come to rest after collision,
Final momentum = 0
Let my velocity be v, and mass, m1 = 60 kg
Friend's mass, m2 = 100 kg
Friend's velocity, v2 = 3 m/s
Intial momentum = m1v + m2v2
= 60v + 300
Conserving momentum,
60v + 300 = 0
v= -5 m/s
( Negative sign indicates that me and my friend are moving in opposite directions that is towards each other)
<h3><u>Answer;</u></h3>
Argon
<h3><u>Explanation;</u></h3>
- Phosphorus is an element found in group 15 of the periodic table, it is one of the element that belongs to nitrogen family.
- The element phosphorus exhibits allotrophy, namely; white phosphorus, red phosphorus and black phosphorus.
- <u>Phosphorus, particularly the white phosphorus combines with oxygen so easily that it catches fire automatically. Thus, as a safety precaution, white phosphorus is stored under water in laboratories.
</u>
- <u>It may be also stored in argon, since argon is an inert element which belongs to the noble gases group.</u>
D. Reflects
The object absorbs the rest of the color spectrum