A student holds a bike wheel and starts it spinning with an initial angular speed of 9.0 rotations per second. The wheel is subj
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Answer:
The height above the waterline that the stream reaches at the horizontal position of the insect is 15 cm.
Explanation:
Please, see the attached figure for a description of the problem.
The motion is parabolic and this is the equation that describes the position of an object in such a motion:
r = (x0 + v0 · t · cos α, y0 + v0 · t · sin α + 1/2 · g · t²)
Where:
r = position vector
x0 = initial horizontal position
v0 = initial velocity
t = time
α = angle of the stream with the waterline
y0 = initial vertical position
g = acceleration due to gravity
First, let´s calculate how much time it takes the stream to reach the horizontal position of 0.27 m. For this, we will use the equation of the x-component of the vector position:
x = x0 + v0 · t · cos α
Since the origin of the reference system is located at the mouth of the fish, x0 = 0. Then:
0.27 m = 3.7 m/s · t · cos 35º
t = 0.27 m /(3.7 m/s · cos 35º)
t = 0.089 s
Now, with this time, we can calulate the vertical position (height) of the stream using the equation for the y-component of the vector "r":
y = y0 + v0 · t · sin α + 1/2 · g · t²
y = 0 m + 3.7 m/s · 0.089 s · sin 35º + 1/2 · (-9.8 m/s²) · (0.089s)²
y = 0.15 m
when the stream reaches 27 cm horizontally, it will reach 15 cm vertically and hit the insect!
Both vehicles experience the same change in momentum.
When the compact car rear ends a truck, they exert equal forces on each other, in accordance with Newton's third law. The force exerted by the car on the truck is equal to the force exerted by the truck on the car.The force acting on the two bodies act for the same interval of time.
According to Newton's second law, the force acting on a body is equal to the rate of change of momentum.
Since the forces are equal,
therefore, the change in momentum of the car is equal to the change in the momentum of the truck
.
Thus, both the car and the truck experience the same change in their momentum. However due to the smaller mass of the car, the change in its velocity is greater than the change in the truck's velocity, which has a larger mass.
Answer:
4.9 m/s
Explanation:
Since the motion of the ball is a uniformly accelerated motion (constant acceleration), we can solve the problem by using the following suvat equation:
where
v is the final velocity
u is the initial velocity
a is the acceleration
s is the distance covered
For the ball in this problem,
u = 0 (it starts from rest)
is the acceleration
s = 3 m is the distance covered
Solving for v,