A ball is dropped from a building taking 3sec to fall to the ground. Calculate:
1 answer:
Answer:
Vf = 29.4 m/s
h = 44.1 m
Explanation:
Data:
- Initial Velocity (Vo) = 0 m/s
- Gravity (g) = 9.8 m/s²
- Time (t) = 3 s
- Final Velocity (Vf) = ?
- Height (h) = ?
==================================================================
Final Velocity
Use formula:
- Vf = g * t
Replace:
- Vf = 9.8 m/s² * 3s
Multiply:
- Vf = 29.4 m/s
==================================================================
Height
Use formula:
Replace:
Multiply time squared:
Simplify the s², and multiply in the numerator:
It divides:
What is the velocity when falling to the ground?
The final velocity is <u>29.4 meters per seconds.</u>
How high is the building?
The height of the building is <u>44.1 meters.</u>
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This question involves the concepts of the law of conservation of momentum and velocity.
The velocity of the eight ball is "5.7 m/s".
According to the law of conservation of momentum:
where,
m₁ = mass of number three ball = 5 g
m₂ = mass of the eight ball = 6 g
u₁ = velocity of the number three ball = 3 m/s
u₂ = velocity of the eight ball = - 1 m/s (negative sign due to opposite direction)
v₁ = final velocity of the three number ball = - 5 m/s
v₂ = final velocity of the eight ball = ?
Therefore,
(5 g)(3 m/s) + (6 g)(- 1 m/s) = (5 g)(- 5 m/s) + (6 g)(v₂)
<u>v₂ = 5.7 m/s</u>
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Learn more about the law of conservation of momentum here:
1. • Here, force of gravity on the block = 20 N.
• Therefore, the normal force will also be the same, i.e., 20 N [According to Newton's Third Law, on every action, there is an equal and opposite reaction]
• The coefficient
• Force of friction =
• Hence, the force of sliding friction between the block and the ground is 8 N.
• So, it is option c. 8 N
2. The answer is option d. continue in the same direction with no change in speed.
We know, force = mass × acceleration. When force is 0, then acceleration will also be 0 since mass cannot be 0. So, there will be no change in speed.
3. It is option b. force that is required to give a one kilogram object the acceleration of 1 m/s^2.
Newton is the SI unit of force. As mentioned earlier, force = mass × acceleration. The SI unit of mass and acceleration is Kg and m/s^2 respectively.
So, 1 N = 1 Kg × 1 m/s^2.
4. It is d. not zero.
Acceleration is the change in speed. So, if the force is zero, then acceleration will not occur.
5. Force = 2 N
Acceleration of the object A = 2 m/s^2.
Acceleration of the object B = 1 m/s^2.
Therefore, mass of the object A = 2 N ÷ 2 m/s^2 = 1 Kg
And, mass of the object B = 2 N ÷ 1 m/s^2 = 2 Kg
So, the mass of object B is greater than that of object A.
Hence, the answer is option c. Object B has more mass.
Hope you could get an idea from here.
Doubt clarification - use comment section.