Answer:
a) 70 N, b) b. Each initially applied a force bigger than static friction to get the box moving and accelerating, then when the desired final speed was achieved they reduced the force to make the net force zero.
Explanation:
a) A constant speed means that magnitude of friction force is equal to the magnitude of the external force. The friction force is directly proportional to the normal force, which is equal to the weight of the box. Therefore, the magnitude of the force is 70 N.
b) Alice used initially a greater force to accelerate the box up to needed speed and later reduced the external force to keep speed constant. The right choice is option b.
There is no apparatus for it. It is either use something like ruler and table and rub together or rub our hands, and friction force will be showed.
Answer:
Option B, two walls and the floor
Explanation:
The distance should be measured from the point where at least the three axed meet.
Two walls and the floor are equivalent to three axes.
Vertical wall 1 = Y Axis
Horizontal wall2 = X Axis
Floor = Z Axis
Thus, the distance should be measured from the point where two walls and one floor meet.
Option , B is correct
Answer:
Explanation:
Since the universal SI unit for velocity is meters/second, let's convert ft/s to m/s:
We can use the following kinematics equation to solve this question:
What we know:
- The initial velocity,
, is 
- (physics concept) The final velocity must be equal in magnitude but opposite in direction to the initial velocity (
) - Acceleration,
, is acceleration due to gravity at about 
Solving for 
:
