Answer:
acceleration, a = 9.8 m/s²
Explanation:
'A ball is dropped from the top of a building' indicates that the initial velocity of the ball is zero.
u = 0 m/s
After 2 seconds, velocity of the ball is 19.6 m/s.
t = 2s, v = 19.6 m/s
Using
v = u + at
19.6 = 0 + 2a
a = 9.8 m/s²
Answer:
The correct solution is "15 kgm/s". A further explanation is given below.
Explanation:
The given values are:
Mass,
m = 5 kg
Velocity,
v = 3 m/s
By applying the formula of momentum, we get
⇒ 
On substituting the given values, we get
⇒ 
⇒ 
Answer: Whenever important physicists are discussed, Galileo Galilei, Isaac Newton, and Albert Einstein seem get the most attention. However, as you’ve seen, Galileo formulated or refined many of his discoveries and theories based on the findings of others who came before him, including Aristotle
Explanation:
Whenever important physicists are discussed, Galileo Galilei, Isaac Newton, and Albert Einstein seem get the most attention. However, as you’ve seen, Galileo formulated or refined many of his discoveries and theories based on the findings of others who came before him, including Aristotle
Answer:
d = 120 [m]
Explanation:
In order to solve this problem, we must use the theorem of work and energy conservation. Where the energy in the final state (when the skater stops) is equal to the sum of the mechanical energy in the initial state plus the work done on the skater in the initial state.
The mechanical energy is equal to the sum of the potential energy plus the kinetic energy. As the track is horizontal there is no unevenness, in this way, there is no potential energy.
E₁ + W₁₋₂ = E₂
where:
E₁ = mechanical energy in the initial state [J] (units of Joules)
W₁₋₂ = work done between the states 1 and 2 [J]
E₂ = mechanical energy in the final state = 0
E₁ = Ek = kinetic energy [J]
E₁ = 0.5*m*v²
where:
m = mass = 60 [kg]
v = initial velocity = 12 [m/s]
Now, the work done is given by the product of the friction force by the distance. In this case, the work is negative because the friction force is acting in opposite direction to the movement of the skater.
W₁₋₂ = -f*d
where:
f = friction force = 36 [N]
d = distance [m]
Now we have:
0.5*m*v² - (f*d) = 0
0.5*60*(12)² - (36*d) = 0
4320 = 36*d
d = 120 [m]
Without friction, we would not be able to stop walking since we would just keep slipping like on ice.
Without friction, objects would just slip and fall with a simple blow of air
And finally without friction we wouldn't be able to use machinery like cars and etc since they would just fly off
Hope this helps!
(tell me if im right)
