How will the weight of an 20kg object change if it was in a lift that accelerates downwards at 4m.s-1
The weight as measured on a scale would be reduced by M*a,
from M*g to M*(g-a)
where a is the downward acceleration.
That is a reduction of 4/9.8 = 40.8%
If the scale is calibrated in kg, it would read 14.8 kg. They may want you to convert that to Newtons.
When an object is moving downwards its weight is 0kg.Because is in free-fall experiences the gravitational force.
To understand how the weight of a 20kg object would change in a lift that accelerates downwards at 4m/s², we need to use the concept of Newton's second law of motion, which states that the force acting on an object is equal to its mass multiplied by its acceleration (F = m * a).
The weight of an object is the force acting on it due to gravity. By default, the acceleration due to gravity is approximately 9.8m/s² and is denoted by the symbol "g". So, the weight of the object can be calculated by multiplying its mass (m) by the acceleration due to gravity (g).
Weight = mass * acceleration due to gravity
In this case, the object has a mass of 20kg. Since the lift is accelerating downwards at 4m/s², we need to modify the acceleration term in the formula. The net acceleration acting on the object is the acceleration due to gravity (g) minus the acceleration of the lift (a).
Net acceleration = g - a
Net acceleration = 9.8m/s² - 4m/s²
Net acceleration = 5.8m/s²
Now we can calculate the weight of the object in the accelerating lift using the modified acceleration.
Weight = mass * net acceleration
Weight = 20kg * 5.8m/s²
Weight = 116N
Therefore, in the lift that accelerates downwards at 4m/s², the weight of the 20kg object will be 116N.