Answer : The time required is, 16.1 minutes.
Explanation :
First we have to calculate the amount of heat required to increase the temperature is:


where,
Q = amount of heat required = ?
m = mass
= density of air = 
V = volume of air
C = specific heat of air = 
= change in temperature = 
Now put all the given values in above formula, we get:



Now we have to calculate the time required.
Formula used :

where,
t = time required = ?
Q = amount of heat required = 
P = power = 1500 W
Now put all the given values in above formula, we get:


Thus, the time required is, 16.1 minutes.
What did the protoplanets become?
a. nebulae
b. planets
c. solar nebulae
d. planetesimals
The protoplanets
become nebulae. The answer is letter A. The
rest of the choices do not answer the question above.
Answer:
The rise in height of combined block/bullet from its original position is 0.45m
Explanation:
Given;
mass of bullet, m₁ = 12 g = 0.012 kg
mass of block of wood, m₂ = 1 kg
initial speed of bullet, u₁ = 250 m/s.
initial speed of block of wood, u₂ = 0
From the principle of conservation of linear momentum, calculate the final speed of the combined block/bullet system.
m₁u₁ + m₂u₂ = v(m₁+m₂)
where;
v is the final speed of the combined block/bullet system.
0.012 x 250 + 0 = v (0.012 + 1)
3 = v (1.012)
v = 3/1.012
v = 2.96 m/s
From the principle of conservation of energy, calculate the rise in height of the block/bullet combined from its original position.
¹/₂mv² = mgh
¹/₂v² = gh
¹/₂ (2.96)² = (9.8)h
4.3808 = 9.8h
h = 4.3808/9.8
h = 0.45 m
Therefore, the rise in height of combined block/bullet from its original position is 0.45m
Answer:
b) Equal to c
Explanation:
According to relativity, the speed of light in free space is constant in all inertial reference frame.
Answer:
E(final)/E(initial)=2
Explanation:
Applying the law of gauss to two parallel plates with charge density equal σ:

So, if the charge is doubled the Electric field is doubled too
E(final)/E(initial)=2