Answer:
A: The acceleration is 7.7 m/s up the inclined plane.
B: It will take the block 0.36 seconds to move 0.5 meters up along the inclined plane
Explanation:
Let us work with variables and set
As shown in the attached free body diagram, we choose our coordinates such that the x-axis is parallel to the inclined plane and the y-axis is perpendicular. We do this because it greatly simplifies our calculations.
Part A:
From the free body diagram we see that the total force along the x-axis is:
Now the force of friction is 
where 
is the normal force and from the diagram it is 
Thus 
Therefore,
Substituting the value for 
we get:
Now acceleration is simply
The negative sign indicates that the acceleration is directed up the incline.
Part B:
Which can be rearranged to solve for t:
Substitute the value of 
and 
and we get:
which is our answer.
Notice that in using the formula to calculate time we used the positive value of 
, because for this formula absolute value is needed.
Answer:
can you post the full question plz
Explanation:
Answer:
Explanation:
Given
mass of book(m)=2.1 kg
height up to which book is lifted is (h)2.2 m
height of person 
Potential energy of book relative to ground=mgh
(b)PE w.r.t to person head =mg(h-h0)
work done by person in lifting box 2.2 m w.r.t floor
Word done =Potential Energy of box relative to floor=45.2 J
Answer:
The resultant velocity of the boat = 5 m/s
The time it will take for the man to reach the other shore of the river = 25 s
Explanation:
width of river = 100 m
The velocity of the motorboat = 4 m/s eastward
The velocity of the water current = 3 m/s northward
The resultant velocity of the boat is:
R^2 = 4^2 + 3^2
= √ (4^2) + (3^2)
= √16 + 9
=√25
= 5 m/s
The time it will take for the man to reach the other shore of the river is:
d = 100 m
v = 4 m/s
t = d / v
t = 100 / 4
t = 25 s
The answer is observation
