Answer:
D. 48.985 N
Explanation:
Newton's second law states that:
which means that the net force acting on an object is equal to the product between the object's mass and its acceleration.
The equation of the forces for the briefcase in the elevator therefore is given by:
where
N is the normal reaction exerted on the briefcase
(mg) is the weight of the briefcase, with
m = 4.5 kg being its mass
g = 9.8 m/s^2 is the acceleration of gravity
a = 1.10 m/s^2 is the acceleration
Here we chose upward as positive direction.
Solving for N, we find the normal force:
So the closest answer is
D. 48.985 N
Answer:
The mass of coal is 108 kg.
Explanation:
Given that,
Energy of coal = 1200 kg
Mass of aluminum = 1.0 kg
Energy required for single soda can = 15 g of Al
Energy required for 6 pack of cans = 
We need to calculate the mass of coal
Using formula of mass
Put the value into the formula
Put the value into the formula
Hence, The mass of coal is 108 kg.
Answer:
6 m/s
Explanation:
Well we can find acceleration a=v/t = (21-0)/7=3 m/s^2
vf=at+v0, use this equation to solve for the vf
vf=3(2)+0=6 m/s was its speed at 2s
Answer:
w = 0.886 rad / s
Explanation:
Angular and linear variables are related
a = α r
where a is the linear acceleration, α the angular acceleration and r the radius of gyration
α = a / r
the angular velocity we can find it
w² = w₀² + 2 α θ
the initial angular velocity is zero, the angles to be horizontal is
θ = π/ 2 rad
we substitute
w = √ 2 a / r θ
we calculate
w = √ (2 3/12 π/2)
w = 0.886 rad / s
