Which of the following statements is TRUE? A. Pollen, cat hair, and mold could trigger an asthma attack for some people. B. Asth
1 answer:
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1. Weight is the gravitational pull with which the earth attracts the body towards the center of the earth. The S.I unit is Newton (N)
2. The weight of an object is related to its mass with the below equation.
W = mg
Where W = weight, m = mass and g = acceleration due to gravity
3. The mass m = 50 kg and g = 9.8 m/
Substitute the parameters in the equation above.
W = 50 x 9.8
W = 490 N
4. An object is accelerating when it speeds up. If the object slows down, it means it is decelerating. The correct answer is option A
5. Newton's second law of motion is:
F = ma
Where F = force applied, m = mass and a = acceleration
Therefore, Newton's second law of motion relates an object's acceleration to its net force acting on it. The correct answer is option C
6. According to Newton's second law of motion which relates an object's acceleration to its mass, doubling the net force acting on an object a doubles its acceleration. Because mass is always constant.
7. Since the weight of an object is related to its mass with the equation.
W = mg, If the mass of an object doubles, its weight will also doubles. Option A is the correct answer.
8. If you know the mass of an object, you can calculate its weight with the formula F = mX when X = 9.8m/
9. Force is expressed in unit as Newton (N)
10. The parameters given are :
mass m = 20kg
Force F = 40N
To calculate acceleration, use the formula F = ma
Substitute all the parameters into the equation.
40 = 20a
a = 40/20
a = 2m/
The correct option is D
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Answer:
Minimum work = 5060 J
Explanation:
Given:
Mass of the bucket (m) = 20.0 kg
Initial speed of the bucket (u) = 0 m/s
Final speed of the bucket (v) = 4.0 m/s
Displacement of the bucket (h) = 25.0 m
Let 'W' be the work done by the worker in lifting the bucket.
So, we know from work-energy theorem that, work done by a force is equal to the change in the mechanical energy of the system.
Change in mechanical energy is equal to the sum of change in potential energy and kinetic energy. Therefore,
Therefore, the work done by the worker in lifting the bucket is given as:
Now, plug in the values given and solve for 'W'. This gives,
Therefore, the minimum work that the worker did in lifting the bucket is 5060 J.