Answer:
B)
Explanation:
The value the scale shows is the reaction force to the normal force (they are equal by Newton's 3rd Law) that the scale exerts on Eric.
The forces on Eric are his weight (downward) and this normal force (upward), so we can write the net force over him as (also using Newton's 2nd Law):
which means
and for our values this is:
Answer:
306500 N/C
Explanation:
The magnitude of an electric field around a single charge is calculated with this equation:
With ε0 = 8.85*10^-12 C^2/(N*m^2)
Then:
E(0.89) = 306500 N/C
Given data
The angle of inclination of the plane is theta = 30 degree
The applied force in the inclined plane is F = 94 N
The distance moved in the inclined plane is d = 2.30 m
The coefficient of kinetic friction is u_k = 0.280
The free-body diagram of the above configuration is shown below:
Here, the normal reaction force on the box is N, the acceleration due to gravity is denoted as g, the friction force on the box is F_f, and the mass of the box is denoted as m.
(a)
The expression for the work done by the pushing force is given as:
Substitute the value in the above equation.
Thus, the work done by the pushing force is 216.2 J.
(b)
The box is moving at the constant velocity, therefore, the pushing force will be equal to the frictional force and the component of the gravitational force in the inclined plane.
The expression for the normal reaction force is given as:
The expression for the mass of the box is given as:
Substitute the value in the above equation.
Thus, the mass of the box is 12.9 kg.
