Hi there!
(a)
Recall that:
W = Work (J)
F = Force (N)
d = Displacement (m)
Since this is a dot product, we only use the component of force that is IN the direction of the displacement. We can use the horizontal component of the given force to solve for the work.
To the nearest multiple of ten:
(b)
The object is not being displaced vertically. Since the displacement (horizontal) is perpendicular to the force of gravity (vertical), cos(90°) = 0, and there is NO work done by gravity.
Thus:
(c)
Similarly, the normal force is perpendicular to the displacement, so:
(d)
Recall that the force of kinetic friction is given by:
Since the force of friction resists the applied force (assigned the positive direction), the work due to friction is NEGATIVE because energy is being LOST. Thus:
In multiples of ten:
(e)
Simply add up the above values of work to find the net work.
Nearest multiple of ten:
(f)
Similarly, we can use a summation of forces in the HORIZONTAL direction. (cosine of the applied force)
Nearest multiple of ten:
Question 9 is 100 N.
Question 10 is No, the bike's motion is not changing so it could be at rest or moving at a constant velocity.
Question 11 is Be doubled.
Question 12 is Ella is correct.
Hope i helped.
If the box is moving at constant velocity, net force must be zero, so:
F + fr = 0
fr = -F
<u>fr = -40 N</u>
Answer:
The mass of the child + skateboard is 50 kg
Explanation:
In this problem, we can apply Newton's second law:
F = ma
where
F is the net force on a system
m is the mass of the system
a is the acceleration of the system
In this problem, our system is the child + the skateboard. The net force on them is
F = 75 N
and their acceleration is
So we can re-arrange the equation above to find their combined mass:
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"H</span>alf-life" is the term among the following that <span>refers to the time it takes for one-half of the radioactive atoms in a sample of a radioactive element to decay. The correct option is option "d".</span>
