Answer:
Negative sign shows that velocity of the car is decreases at a constant rate
Explanation:
We have given velocity of the car is decreases from 32 m /sec to 24 m/sec in 4 second
So initial velocity of the car u = 32 m /sec
And finally car reaches to a velocity of 24 m/sec
Time taken to change in velocity = 4 sec
So final velocity v = 24 m/sec
From first equation of motion v = u+at
So 
Negative sign shows that velocity of the car is decreases at a constant rate
Answer:
One way to test the hypothesis is to create two waves, one in the air and one on the ground at the same time. One of them for the elephant to get closer and another for the elephants to move away. Observe the reaction of the animal and with this we know which sound came first.
Explanation:
This hypothesis is based on the fact that the speed of sound in air is v = 343 m / s with a small variation with temperature.
The speed of sound in solid soil is an average of the speed of its constituent media, giving values between
wood 3900 m / s
concrete 4000 m / s
fabrics 1540 m / s
earth 5000 m / s wave S
ground 7000 m / s P wave
we can see that the speed on solid earth is an order of magnitude greater than in air.
One way to test the hypothesis is to create two waves, one in the air and one on the ground at the same time. One of them for the elephant to get closer and another for the elephants to move away. Observe the reaction of the animal and with this we know which sound came first.
From the initial information, the wave going through the ground should arrive first.
Explanation:
Take F=ma
a = F/m
For a higher, F higher or m lower
Means higher horse power for engine or lower mass for the car
If a force always acts perpendicular to an object's direction of motion, that force cannot change the object's kinetic energy. It is a true statement .
Kinetic energy is the energy that an object possesses due to its motion. It is basically the energy of mass in motion. Kinetic energy can never be negative and it is a scalar quantity i.e. it provides only the magnitude and not the direction.
According to law of conservation of mechanical energy change in potential energy is equal and opposite to the change in the kinetic energy.
According to the principle of conservation of mechanical energy, The total mechanical energy of a system is conserved i.e., the energy can neither be created nor be destroyed; it can only be internally converted from one form to another if the forces doing work on the system are conservative in nature.
since, potential energy is stored in the form of work done
Work done = Fs cos (theta)
If force always acts perpendicular to an object's direction of motion
theta = 90 °
cos (90 ) = 0
Work done = 0
since , there is no work done , hence kinetic energy will not change
To learn more about kinetic energy here
brainly.com/question/12669551
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