You throw a ball horizontally off a building with a horizontal velocity of 10m/s. What is the ball's horizontal velocity 5 seconds later. What is the ball's vertical velocity 5 seconds later?
There is no horizontal force.
Therefore the horizontal velocity REMAINS CONSTANT
v = - g t = -9.81*5 = 49 m/s down
To find the ball's horizontal velocity 5 seconds later, we can assume that there is no horizontal acceleration. This means that the horizontal velocity remains constant over time.
Given that the initial horizontal velocity is 10 m/s, we can conclude that the ball's horizontal velocity 5 seconds later is also 10 m/s.
Now let's calculate the ball's vertical velocity 5 seconds later.
Considering the ball is thrown horizontally, there is no initial vertical velocity. However, we need to take into account the effect of gravity on the ball's vertical motion.
The acceleration due to gravity is approximately 9.8 m/s², and it acts vertically downwards. Since the ball is in free-fall, its vertical velocity increases at a rate of -9.8 m/s².
Using the formula for vertical velocity in free-fall motion:
v = u + at
where:
v is the final vertical velocity,
u is the initial vertical velocity,
a is the acceleration, and
t is the time.
Substituting the values:
v = 0 m/s + (-9.8 m/s²) * 5 s
v = 0 m/s - 49 m/s
v = -49 m/s
Therefore, the ball's vertical velocity 5 seconds later is -49 m/s. Note that the negative sign indicates that the ball is moving downwards.
To find the ball's horizontal velocity 5 seconds later, we need to know two things: the initial horizontal velocity and the fact that there is no horizontal acceleration.
Given that the initial horizontal velocity is 10 m/s and there is no horizontal acceleration, the ball's horizontal velocity will remain constant over time. Therefore, the ball's horizontal velocity 5 seconds later will still be 10 m/s.
Now, let's move on to finding the ball's vertical velocity 5 seconds later. To do this, we need to consider the effect of gravity.
When the ball is thrown horizontally, its vertical velocity initially is zero because there is no vertical component to its motion. However, due to the force of gravity, the ball will start to accelerate downward. The formula for vertical velocity can be expressed as:
Vertical velocity (Vv) = Initial vertical velocity (Vvi) + (acceleration due to gravity x time)
Keep in mind that the acceleration due to gravity is approximately 9.8 m/s², and its value is negative because it acts in the downward direction.
So, in this case, the initial vertical velocity is zero, and the time is 5 seconds. Substituting these values, we get:
Vv = 0 + (-9.8 m/s² x 5 s)
Vv = 0 - 49 m/s
Vv = -49 m/s
Therefore, the ball's vertical velocity 5 seconds later will be -49 m/s.