Answer:
The mass of the second person is 28.91 kg
Explanation:
Given;
mass of the first adult, m₁ = 54.2 kg
distance of the first adult from the point of balance, x = 1.20 m
mass of the second adult, = m₂
distance of the second adult from the point of balance, y = 2.25 m
Taking moment about the point of balance, we will have
m₁x = m₂y
54.2 x 1.2 = 2.25y
2.25y = 65.04
y = 65.04/2.25
y = 28.91 kg
Therefore, the mass of the second person is 28.91 kg
Answer:
a)
, b) 
Explanation:
The magnitude of torque is a form of moment, that is, a product of force and lever arm (distance), and force is the product of mass and acceleration for rotating systems with constant mass. That is:



Where
is the angular acceleration, which is constant as torque is constant. Angular deceleration experimented by the unpowered flywheel is:


Now, angular velocities of the unpowered flywheel at 50 seconds and 100 seconds are, respectively:
a) t = 50 s.


b) t = 100 s.
Given that friction is of reactive nature. Frictional torque works on the unpowered flywheel until angular velocity is reduced to zero, whose instant is:


Since
, then the angular velocity is equal to zero. Therefore:

Answer:
The change of the momentum of the ball is
Explanation:
We should find
(1)with
the initial momentum and
the final momentum. Linear momentum is defined as
, using that on (1):
(2)
It's important to note that momentum and velocity are vectors and direction matters, so if +x direction is the direction towards the wall and the -x direction away the wall
and
so (2) becomes:

Explanation:
The x component of the resultant force is the sum of the x components of the individual forces.
Fₓ = 65.0 cos 30° − 20.0 sin 20° − 30.0
Fₓ = 19.5
The y component of the resultant force is the sum of the y components of the individual forces.
Fᵧ = 65.0 sin 30° − 20.0 cos 20°
Fᵧ = 13.7
The magnitude is found with Pythagorean theorem:
F² = Fₓ² + Fᵧ²
F² = (19.5)² + (13.7)²
F = 23.8