Answer:
The average power the student expended to overcome gravity is 560W, Watts is a units of work it is Joules /time or kg*/
Explanation:
Weight = 700N
The power is the work in (Joules) or (N*m) in a determinate time (s) to get Watts (W) units for work
Newton's second law allows us to find the force of the block on the table is 126 N
Newton's second law says that the net force is proportional to the product of the mass and the acceleration of the body
Σ F = m a
Where the bold letters indicate vectors, m is the mass and the acceleration of the body
A free body diagram is a diagram where the forces are represented without the details of the bodies, in the attached we can see a free body diagram of the system.
Let's start by finding the acceleration of the elevator with kinematics
v = v₀ + a t
a =
Where v and v₀ are the current and initial velocity, respectively, at acceleration and t is the time
a =
a = 3.5 m / s²
Let's write Newton's second law for each body
The book
N₂ - W₂ + N₁ = m a
Table
N₁ - W₁ - W₂ = M a
W₁ = Mg
W₂ = mg
N₁ = (M + m) g + M a
N₁ = (10 + 2) 9.8 + 10 3.5
N₁ = 152.6 N
This is the reaction of the earth to the support of the block and the table
N₂ = ma + m g - N₁
N₂ = m ( a +g) - N₁
N₂ = 2 (3.5 + 9.8) - 152.6
N₂ = 26.6 - 152.6
N₂ = -126 N
The negative sign indicates that the direction is opposite to the one assigned, this is the action of the block on the table.
In conclusion using Newton's second law we can find the forces of the block on the table is 126 N
Learn more here: brainly.com/question/19860811
