Answer:
V = 20 m/s
Explanation:
Given the following data;
Mass = 80kg
Kinetic energy = 16,000 joules
To find the velocity;
Kinetic energy can be defined as an energy possessed by an object or body due to its motion.
Mathematically, kinetic energy is given by the formula;

Where;
K.E represents kinetic energy measured in Joules.
M represents mass measured in kilograms.
V represents velocity measured in metres per seconds square.
Substituting into the formula, we have;
16000 = ½*80*V²
16000 = 40V²
V² = 16000/40
V² = 400
Taking the square root of both sides, we have;
V = 20 m/s
C . plate a is negatively charged and plate b is positively charged
Answer:
The car must be moving away from the person.
Explanation:
From Doppler's Effect, we know that when a sound source moves towards a stationary observer, the apparent frequency of that sound increases. While the apparent frequency decreases if the source moves away from the stationary observer.
The audible range of frequencies for a human ear is 20 Hz to 20000 Hz. Therefore, in order for the sound of a loud speaker to be audible for the person, the frequency must decrease below 20000 Hz.
<u>Due to this reason, the car must be moving away from the person.</u>
Answer:
a) 42 m/s, positive direction (to the east), b) 42 m/s, negative direction (to the west).
Explanation:
a) Let consider that Car A is moving at positive direction. Then, the relative velocity of Car A as seen by the driver of Car B is:

42 m/s, positive direction (to the east).
b) The relative velocity of Car B as seen by the drive of Car A is:

42 m/s, negative direction (to the west).
Answer: The correct answer for the blank is- a. change its position relative to other objects.
Perception of motion can be described as a phenomenon of inferring the direction and speed and of objects, which are moving in a visual scene.
An object is said to be in motion if its position is changed with respect to objects that are present in its surrounding.
Thus, in order to sense motion of objects, humans beings are required to see an object change its position with respect to other objects.