Answer:
ice forming and then melting back into water
Answer:
Double the current
Explanation:
The energy delivered by the heater is related to the current by the following relation:
E= 
let R * t = k ( ∴ R and t both are constant)
so E= k 
Now let:
E2= k I₂^2
E2= 4E
⇒ k I₂^2= 4* k 
Cancel same terms on both sides.
I₂^2= 4* 
taking square-root on both sides.
√I₂^2 = √4* I^2
⇒I₂= 2I
If we double the current the energy delivered each minute be 4E.
3.4m/s
Explanation:
Given parameters:
Distance to school = 14.4km
Time taken by Amy = 49min
Time taken by bill = 20min after Amy = 20+49 = 69min
Unknown parameters:
How much faster is Amy's average speed = ?
Solution:
Average speed is the rate of change of total distance with total time taken.
Average speed = 
convert units to meters and seconds
1000m = 1km
60s = 1min
Distance to school = 14.4 x 1000 = 14400m
Time taken by Amy = 49 x 60 = 2940s
Time taken by Bill = 69 x 60 = 4140s
Average speed of Amy =
= 4.9m/s
Average speed of Bill =
= 1.4m/s
Differences in speed = 4.9 - 1.5 = 3.4m/s
Amy was 3.4m/s faster than Bill
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Average speed brainly.com/question/8893949
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Answer:
5.3 m/s
Explanation:
First, find the time it takes for him to fall 7m.
y = y₀ + v₀ t + ½ at²
0 = 7 + (0) t + ½ (-9.8) t²
0 = 7 − 4.9 t²
t ≈ 1.20 s
Now find the velocity he needs to travel 6.3m in that time.
x = x₀ + v₀ t + ½ at²
6.3 = 0 + v₀ (1.20) + ½ (0) (1.20)²
v₀ ≈ 5.27 m/s
Rounded to two significant figures, the man must run with a speed of 5.3 m/s.
The heat remains constant because there’s nothing to cool it down