Answer:
Explanation:
(a) It is given that Joseph jogs on a straight road of 300m in a time interval of 2 minutes and 30 seconds, which is equal to 150seconds. Therefore, when Joseph jogs from point A to point B, he covers a distance of 300m in time of 150seconds. Hence, his average speed is 300m/150s=2ms^−1. Since it is a straight road and he jogs in a single direction in this case, his displacement is equal to 300m. Since it is a straight road and he jogs in a single direction in this case, his displacement is equal to 300m.
Hence, his average velocity is 300m/150s=2ms^−1
(b) Then it is given that he turns back and points B and jogs on the same road but in the opposite direction for a time interval for 1 minute and covers a distance of 100m.If we consider the whole motion of Joseph, i.e. from point A to point C, then he covers a total distance of 300m+100m=400m. And he covers this total distance in a time interval of 2.5min+1min=3.5min=210s.
Therefore, his average speed for this journey is 400m210s=1.9ms−1.
For the same journey is displacement is equal to the distance between the points A and C,i.e. 300m−100m=200m.
Hence, his average velocity for this case is 200m/210s=0.95ms^−1
velocity=displacement/time
displacement=∆velocity x ∆time
displacement=4x4
16m
If the velocity of the chair is constant, then the net force acting on it is zero.
The force you exert to keep it going is equal and opposite to the force of friction.
To solve the exercise it is necessary to apply the equations necessary to apply Newton's second law and the concept related to frictional force.
An angle of 30 degrees is formed on the vertical at an applied force of 2.3N
In this way the frictional force, opposite to the movement will be given by
where,
Kinetic friction constant
N = Normal Force (Mass*gravity)
The friction force is completely vertical and opposes the rising force of 2.3 N. The Normal force acts perpendicular to the surface (vertical) therefore corresponds to the horizontal component of the applied force.
The ascending force would be given by
As the block is moving upward, the friction force acts downward, also its weight acts downward. We can have
Considering the horizontal force the normal force on the block must be balanced by the horizontal component of pishing foce
Then the frictional force
Therefore the coefficient of kinetic friction is 0.26