Kiley went 5.7 km/h north and then went 5.8 km/h west. From start to finish, she went 8.1 km/h northwest.
2 answers:
Explanation :
Instantaneous velocity: It is defined as the velocity at a particular instant of time.
Average velocity is the ratio of total displacement covered by an object divided by the total time taken.
It is given that, Kiley went 5.7 km/h north and then went 5.8 km/h west. Here, both direction as well as magnitude of velocity is given. This implies the instantaneous speeds.
The resultant of these two velocities would be :
She went 8.1 km/h northwards. This implies resultant velocity i.e. average speed.
So, the correct option is (a).
Hence, this is the required solution.
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Answer:
Friction between the box and the floor is 25N to the left
Explanation:
There are two forces acting on the box along the horizontal direction:
- The force of push applied by the worker, in the forward direction, F
- The force of friction, , acting in the opposite direction (backward)
So the net force acting on the box is
According to Newton's second law of motion, the net force on an object is equal to the product between its mass (m) and its acceleration (a), so we can write:
And so
However, in this case the box is moving at constant speed; this means that its acceleration is zero:
Therefore we have:
Which means
And since we are told that
This means that the force of friction is also 25 N: