Brainliest if correct Question 8 of 10

A motor running at 2600 rev/min is suddenly switched off and decelerates uniformly to rest after 10 s. Find the angular decelera

Mama L [17]

Angular acceleration = (change in angular speed) / (time for the change)

change in angular speed = (zero - 2,600 RPM) = -2,600 RPM

time for the change = 10 sec

Angular acceleration = -2600 RPM / 10 sec = -260 rev / min-sec

(-260 rev/min-sec) x (1 min / 60 sec) = -(4 1/3) rev / sec²

Since the acceleration is negative, the motor is slowing down.
You might call that a 'deceleration' of (4 1/3) rev/sec² .

The average speed is 1/2(2,600 + 0) = 1,300 rev/min = (21 2/3) rev/sec.

Number of revs = (average speed) x (time) = (21 2/3) x (10sec) = (216 2/3) revs

6 0

3 years ago

7. A toy car of mass 1.2 kg is driving vertical circles inside a hollow cylinder of radius 2.0m. It is moving at a constant spee

wlad13 [49]

Answer:

a)

$N_{top}=9.8N\\N_{bottom}=33.4N$

b) $v_{min}=4.4m/s$

Explanation:

The net force on the car must produce the centripetal acceleration necessary to make this circle, which is $a_{cp}=\frac{v^2}{R}$ . At the top of the circle, the normal force and the weight point downwards (like the centripetal force should), while at the bottom the normal force points upwards (like the centripetal force should) and the weight downwards, so we have (taking the upwards direction as positive):

$-m\frac{v^2}{R}=-N_{top}-mg\\m\frac{v^2}{R}=N_{bottom}-mg$

Which means:

$N_{top}=m\frac{v^2}{R}-mg=(1.2kg)\frac{(6m/s)^2}{2m}-(1.2kg)(9.8m/s^2)=9.8N\\N_{bottom}=m\frac{v^2}{R}+mg=(1.2kg)\frac{(6m/s)^2}{2m}+(1.2kg)(9.8m/s^2)=33.4N$

The limit for falling off would be $N_{top}=0$ , so the minimum speed would be:

$0=m\frac{v_{min}^2}{R}-mg\\v_{min}=\sqrt{Rg}=\sqrt{(2m)(9.8m/s^2)}=4.4m/s$

3 0

2 years ago

Your bike gets a flat tire. Its mass is 10 kg and you are able to accelerate your bike .5 m/s/s. What is the force on the bike..

STALIN [3.7K]

Answer:

50N

Explanation:

Given parameters:

Mass of the bike = 10kg

Acceleration = 5m/s²

Unknown:

Force on the bike = ?

Solution:

To solve this problem, we apply Newton's second law of motion.

Force = mass x acceleration

Force = 10 x 5 = 50N

6 0

2 years ago

A rod made from insulating material carries a net charge, while a copper sphere is neutral. The rod and the sphere do not touch.

navik [9.2K]

As the charged insulating rod approaches the sphere (not in contact), free electrons in the sphere move. If the rod is negatively charged, free electrons move to the side of the sphere opposite the side with the rod. If the rod is positively charged, the free electron moves to the side of the sphere with the rod. In either case, the region of the sphere near the rod acquires a charge with the sign opposite to that on the rod.

a. Since opposedly charged objects always attract each other, the rod and ball always experience mutual attractive forces.

b. Since the side of the sphere near the bar always has the opposite charge to the charge of the rod, the rod and the sphere always attract each other. They do not repel each other.

3 0

2 years ago

After the box comes to rest at position x₁, a person starts pushing the box, giving it a speed v₁. When the box reaches position

Vesna [10]

Answer:

$W_p = \frac{1}{2}mv_1^2$