The average speed would be 0.65 m/s, therefore the correct option is (A).
The average speed is calculated by the formula
Average speed= (total distance/ total time)
The total distance of the trip=9.5+3.5+15=28 m
The total time of trip=43 sec
Therefore the average speed=28/43=0.65 m/s.
Answer:
3120J
Explanation:
Given parameters:
C = Specific heat capacity = 0.8J/g°C
Initial temperature = 20°C
Mass given = 5g
Final temperature = 800°C
Unknown:
Energy given to the mass = ?
Solution:
To find the energy given to the mass, let us simply use the expression below:
H = m c ΔT
H is the unknown, the energy supplied
m is the mass of the substance
c is the specific heat capacity
ΔT is the change in temperature
Input the variables;
H = 5 x 0.8 x (800 - 20) = 3120J
Answer:
They will move the fridge if they all push in the same direction, but it will not move with constant velocity
Explanation:
The maximum static friction force is
(negative sign since its direction is opposite to the push applied by the people)
Sam can apply a force of 130 N, while Amir and Andre can apply a push of 65 N each, so the total force that they can apply, if they push in the same direction, will be:

This force is larger than the frictional force, so the fridge will start moving.
However, the net force on the fridge will be:

And according to Newton's second law,

where m is the mass of the fridge and a its acceleration, since the net force is not zero, then the fridge will have a non-zero acceleration, so it will not move with constant velocity.
Models help us to understand systems and their properties
Answer:
the distance that the object is raised above its initial position is 5.625 m.
Explanation:
Given;
applied effort, E = 15 N
load lifted by the ideal pulley system, L = 16 N
distance moved by the effort, d₁ = 6 m
let the distance moved by the object = d₂
For an ideal machine, the mechanical advantage is equal to the velocity ratio of the machine.
M.A = V.R

Therefore, the distance that the object is raised above its initial position is 5.625 m.