Answer: height = 3.98m
Explanation: by placing the watermelon at a height above the ground, it has a potential energy of the formulae
p = mgh
p = potential energy = 4.61kJ = 4610J
m = mass of watermelon = 118 kg
g = acceleration due gravity = 9.8 m/s²
4610 = 118 * 9.8 * h
h = 4610/ 118 * 9.8
h = 4610/ 1156.4
h = 3.98m
Answer:
– 2.5 m/s²
Explanation:
We have,
• Initial velocity, u = 180 km/h = 50 m/s
• Final velocity, v = 0 m/s (it stops)
• Time taken, t = 20 seconds
We have to find acceleration, a.
a = (v ― u)/t
a = (0 – 50)/20 m/s²
a = –50/20 m/s²
a = – 5/2 m/s²
a = – 2.5 m/s² (Velocity is decreasing) [Answer]
Answer:
proof in explanation
Explanation:
First, we will calculate the number of half-lives:
where,
n = no. of half-lives = ?
t = total time passed = 2100 million years
= half-life = 700 million years
Therefore,
Now, we will calculate the number of uranium nuclei left ():
and the rest of the uranium nuclei will become thorium nuclei ()
dividing both:
<u>Hence, it is proven that after 2100 million years there are seven times more thorium nuclei than uranium nuclei in the rock.</u>
12 V is the f.e.m.
of the battery. The potential difference that is applied to the motor is actually the fem minus the voltage drop on the internal resistance r:
this is equal to the voltage drop on the resistance of the motor R:
so we can write:
and using
and
we can find the current I: