Answer:
Explanation:
Given
Each student exert a force of 
Let mass of car be m
there are 18 students who lifts the car
Total force by 18 students 
therefore weight of car 
mass of car 

(b)
Answer:
0.45 seconds
Explanation:
Letting the value of g = 10 m/s/s
final velocity (v) = 0 m/s (since the egg will come to rest at the maximum height)
initial velocity(u) = 4.5 m/s
acceleration = -10 m/s/s (since the gravity is acting against the egg)
time = t seconds
From the first equation of motion:
<em>v = u + at</em>
<em>0 = 4.5 + (-10)t</em>
<em>t = -4.5 / -10</em>
t = 0.45 seconds
Answer:
ΔX = λ = 0.68 m
Explanation:
Wave speed is related to wavelength and frequency by the equation
v = λ f
where the speed of sound is 340 m / s
λ = v / f
λ = 340/500
λ = 0.68 m
this is the wavelength, it is the minimum distance for which the wave epitates its movement, which is equal to the distance between two consecutive compressions of the sound
ΔX = λ = 0.68 m
To solve the problem, it is necessary the concepts related to the definition of area in a sphere, and the proportionality of the counts per second between the two distances.
The area with a certain radius and the number of counts per second is proportional to another with a greater or lesser radius, in other words,


M,m = Counts per second
Our radios are given by



Therefore replacing we have that,






Therefore the number of counts expect at a distance of 20 cm is 19.66cps
Potential energy<span> is the </span>energy<span> that is stored in an object due to its position relative to some zero position. It is calculated by the expression PE = mgh where mg is the weight of the book and h is the height. It is calculated as follows:
PE = 50(1) = 50 J
</span>PE = 50(1.5) = 75 J
PE = 50(2) = 100 J