In scientific notation", that number would be written as
6.81 x 10⁻⁴ .
Answer:
90,000 J
Explanation:
Kinetic energy can be found using the following formula.

where <em>m </em>is the mass in kilograms and <em>v</em> is the velocity in m/s.
We know the object has a mass of 50 kilograms. We also know it is a traveling at a rate of 60 m/s. Velocity is the speed of something, so the velocity of the object is 60 m/s.
<em>m</em>=50
<em>v</em>=60
Substitute these values into the formula.

First, evaluate the exponent: 60^2. 60^2 is the same as multiplying 60, 2 times.
60^2=60*60=3,600

Multiply 50 and 3,600

Multiply 1/2 and 3,600, or divide 3,600 by 2.

Add appropriate units. Kinetic energy uses Joules, or J.

The kinetic energy of the object is 90,000 Joules
Solution :
Given
Diameter of the roulette ball = 30 cm
The speed ball spun at the beginning = 150 rpm
The speed of the ball during a period of 5 seconds = 60 rpm
Therefore, change of speed in 5 seconds = 150 - 60
= 90 rpm
Therefore,
90 revolutions in 1 minute
or In 1 minute the ball revolves 90 times
i.e. 1 min = 90 rev
60 sec = 90 rev
1 sec = 90/ 60 rec
5 sec = 
= 75 rev
Therefore, the ball made 75 revolutions during the 5 seconds.
The answer is :78 I think
C. Gamma rays have more energy than infrared rays