A flywheel having constant angular acceleration requires 4.70 s to rotate through 164 rad . Its angular velocity at the end of t
1 answer:
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Answer:
Explanation:
The cabinet does not move: this means that the net force acting on it is zero.
Along the horizontal direction, we have two forces:
- The push exerted by Bob, F = 200 N, forward
- The frictional force, , which acts in the opposite direction (backward)
Since the net force must be zero, we have:
So solving the equation we can find the magnitude of the friction force:
(a)
First of all, we need to calculate the acceleration of the person, by using the following SUVAT equation:
where
v = 0 is the final velocity
u = 20.0 m/s is the initial velocity
a is the acceleration
d = 1.00 cm = 0.01 m is the displacement of the person
Solving for a,
And the average force on the person is given by
with m = 75.0 kg being the mass of the person. Substituting,
where the negative sign means the force is opposite to the direction of motion of the person.
b)
In this case,
v = 0 is the final velocity
u = 20.0 m/s is the initial velocity
a is the acceleration
d = 15.00 cm = 0.15 m is the displacement of the person with the air bag
So the acceleration is
So the average force on the person is
Answer:
F = -49.1 10³ N
Explanation:
Let's use the kinematics to find the acceleration the acceleration of the bullet that they tell us is constant
² = v₀² + 2 a x
Since the bullet is at rest, the final speed is zero
x = 11.00 cm (1 m / 100 cm) = 0.110 m
0 = v₀² + 2 a x
a = -v₀² / 2 x
a = -1320²/(2 0.110)
a = -7.92 10⁶ m / s²
With Newton's second law we find the force
F = m a
F = 6.20 10⁻³ (-7.92 10⁶)
F = -49.1 10³ N
The sign means that it is the force that the tree exerts to stop the bullet