Answer:
Explanation:
Work is equal to the product of force and distance.
The force is 8 Newtons and the distance is 15 meters.
Substitute the values into the formula.
Multiply.
The work done is <u>120 Joules</u>
Sarah's acceleration is
Explanation:
The force of kinetic friction acting on Sarah has a magnitude which is given by:
where
is the coefficient of kinetic friction
m is Sarah's mass
g is the acceleration of gravity
Moreover, according to Newton's second law of motion, we know that the net force on Sarah is equal to its mass times its acceleration:
where a is the acceleration
Since the force of friction is the only force acting on Sarah, we can say that the net force is equal to the force of friction, therefore:
where the negative sign is due to the fact that the force of friction has a direction opposite to the motion of Sarah. Solving for a, we find
And substituting the following values:
(coefficient of friction)
(acceleration of gravity)
we find:
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The range of the projectile is 188 m
Explanation:
The motion of the arrow in this problem is a projectile motion, so it follows a parabolic path which consists of two independent motions:
- A uniform motion (constant velocity) along the horizontal direction
- An accelerated motion with constant acceleration (acceleration of gravity) in the vertical direction
The path of a projectile is the combination of these two motions: see figure in attachment.
In order to find the horizontal range of the projectile, we just need to calculate the horizontal distance travelled.
We have:
t = 5.0 s (time of fligth of the projectile)
and the horizontal velocity is constant, and it is given by
where
is the initial velocity
is the angle of projection
Substituting,
And therefore, the range of the projectile is:
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