Answer:
<em>The boat takes 2.5 seconds to slow down to 5 m/s</em>
Explanation:
<u>Motion With Constant Acceleration</u>
It's a type of motion in which the velocity of an object changes uniformly in time. The equation that rules the change of velocities is:
![v_f=v_o+at\qquad\qquad [1]](https://tex.z-dn.net/?f=v_f%3Dv_o%2Bat%5Cqquad%5Cqquad%20%5B1%5D)
Where:
a = acceleration
vo = initial speed
vf = final speed
t = time
Using the equation [1] we can solve for a:
The acceleration produced by the friction of water is 
and the boat is initially traveling at v0=30 m/s. When the motor is shut off, the boat will start braking until it stops. We need to find the time it takes to ready the final speed of vf=5 m/s.
Let's solve the above equation for t:
t = 2.5 s
The boat takes 2.5 seconds to slow down to 5 m/s
Answer:
20.1 m/s
Explanation:
Since You are later than usual getting to the stop and see the shuttle pulling away from the stop while you are still 3.9 m behind the bus stop. And In 40.9 m you will reach a barrier and you must catch the shuttle before that point.
Given that the shuttle has a constant acceleration of 4.5 m/s2.
The total distance to cover is:
Total distance = 40.9 + 3.9 = 44.8 m
Assuming you are starting from rest. Then initial velocity U = 0
Using the 3rd equation of motion to calculate the minimum velocity.
V^2 = U^2 + 2as
V^2 = 0 + 2 × 4.5 × 44.8
V^2 = 403.2
V = sqrt (403.2)
V = 20.1 m/s
Therefore, the minimum velocity you have to run at to catch the bus before it reaches the barrier is 20.1 m/s
Maybe friction..? my best answer.
Answer:
v = R w
With this expression we see that for each point at different radius the tangential velocity is different
Explanation:
They indicate that the angular velocity is constant, that is
w = dθ / dt
Where θ is the radius swept angle and t the time taken.
The tangential velocity is linear or
v = dx / dt
Where x is the distance traveled in time (t)
In the definition of radians
θ = s / R
Where s is the arc traveled and R the radius vector from the pivot point, if the angle is small the arc (s) and the length (x) are almost equal
θ = x / R
We substitute in the speed equation
v = d (θ R) / dt
The radius is a constant for each point
v = R dθ / dt
v = R w
With this expression we see that for each point at different radius the tangential velocity is different
Because plastic and rubber are insulators.
