Answer:
No
Explanation:
The force of tension exerted by the string on the rock acts as centripetal force, so its direction is always towards the centre of the circle.
However, the direction of motion of the rock is always tangential to the circle: this means that the force is always perpendicular to the direction of motion of the rock.
As we know, the work done by a force on an object is
where
F is the magnitude of the force
d is the displacement of the object
is the angle between the force and the displacement
In this situation, F and d are perpendicular, so 
, therefore 
and the work done is zero:
Answer is D. Neutral charge
The horizontal component of the velocity of the ball is calculated by multiplying the speed by the cosine of the given angle.
x-component of speed = (31 m/s)(cos 35°)
= 25.39 m/s
Thus, the horizontal velocity component of the ball is 25.39 m/s.
Answer:
313.6 m downward
Explanation:
The distance covered by the bullet along the vertical direction can be calculated by using the equation of motion of a projectile along the y-axis.
In fact, we have:
where
y(t) is the vertical position of the projectile at time t
h is the initial height of the projectile
is the initial vertical velocity of the projectile, which is zero since the bullet is fired horizontally
t is the time
a = g = -9.8 m/s^2 is the acceleration due to gravity
We can rewrite the equation as
where the term on the left, 
, represents the vertical displacement of the bullet. Substituting numbers and t = 8 s, we find
So the bullet has travelled 313.6 m downward.
