Answer:
80 J
Explanation:
PE = mgh
PE = (4 kg)(9.8 m/s^2)(2 m)
PE = 78.4 J and with sig figs, it would be 80 J
Wavelength and frequency have a reciprocal relationship. If one doubles, the other halves.
Given :
Reem took a wire of length 10 cm. Her friend Nain took a wire of 5 cm of the same material and thickness both of them connected with wires as shown in the circuit given in figure. The current flowing in both the circuits is the same.
To Find :
Will the heat produced in both the cases be equal.
Solution :
Heat released is given by :
H = i²Rt
Here, R is resistance and is given by :

So,
Now, in the question every thing is constant except for the length of the wire and from above equation heat is directly proportional to the length of the wire.
So, heat produced by Reem's wire is more than Nain one.
Hence, this is the required solution.
Answer:
Explanation:
Time taken to accelerate to 28 m /s
= 28 / 2 = 14 s
a ) Total length of time in motion
= 14 + 41 + 5
= 60 s .
b )
Distance covered while accelerating
s = ut + 1/2 at²
= 0 + .5 x 2 x 14²
= 196 m .
Distance covered while moving in uniform motion
= 28 x 41
= 1148 m
distance covered while decelerating
v = u - at
0 = 28 - a x 5
a = 5.6 m / s²
v² = u² - 2 a s
0 = 28² - 2 x 5.6 x s
s = 28² / 2 x 5.6
= 70 m .
Total distance covered
= 196 + 1148 + 70
= 1414 m
total time taken = 60 s
average velocity
= 1414 / 60
= 23.56 m /s .
The ball rolled a distance of
d = 12m + 20m.
But the change of position is
x = + 12m - 20m