Answer:

Explanation:
Given:
mass, 
time, 
velocity, 
coefficient of kinetic friction between wheels & pavement, 
According to first condition,



According to second condition,
<u>Magnitude of frictional force (which acts opposite to the direction of motion):</u>

where N is the normal reaction.


Now, the impulsive force on the wall if the brakes were applied during the crash:



Answer:
266. 4
Explanation:
acceleration due to vravity on earth is 10m/s.
One third of it is (1/3)*10
=3.333m/s.
Weight is mass × acceleration
weight= 80kg÷ 3.333m/s
W= 266.4 Newton.
Answer:
540m/s
Explanation:
Given parameters:
Frequency of the wave = 18000Hz
Wavelength of the wave = 0.03m
Unknown:
How fast is the wave traveling = ?
Solution:
How fast the wave is traveling is a measure of the speed of the wave;
Speed of wave = frequency x wavelength
Now insert the given parameters and solve;
Speed of wave = 18000 x 0.03 = 540m/s
(a) The work done by the bird to raise the snake on the branch is equal to the product between the weight of the snake and the height of the branch above the ground:

where
is the mass of the snake and
is the height of the branch with respect to the ground. Substituting numbers into the equation, we find

(b) The work the bird did to raise its own centre of mass from the ground to the branch is equal to the product between the bird's weight and the height of the branch:

where
is the mass of the bird. Substituting numbers into the equation, we find

Answer:
DNA contains the instructions needed for an organism to develop, survive and reproduce. To carry out these functions, DNA sequences must be converted into messages that can be used to produce proteins, which are the complex molecules that do most of the work in our bodies