Ask question

Ask question

All categories

3 years ago

10

The angular speed of an automobile engine is increased at a constant rate from 1200 rev/min to 3000 rev/min in12 s.(a) What is i

ts angular acceleration in revolutions per minutesquared?(b) How many revolutions does theengine make during this 12 s interval?

1 answer:

Agata [3.3K]3 years ago

8 0

Answer:

The angular acceleration is

=

15.71

r a d s − 2 and the number of revolutions is = 419.9

Explanation:

You might be interested in

You are testing a new amusement park roller coaster with an empty car with a mass 120 kg. One part of the track is a vertical lo

Kay [80]

Answer:

- 5436 J

Explanation:

mass of car, m = 120 kg

radius of loop, r = 12 m

velocity at the bottom (A) = Va = 25 m/s

Velocity at the top(B) = Vb = 8 m/s

Vertical distance from A to B = diameter of loop, h = 2 x 12 = 24 m

by use of Work energy theorem

Work done by all the forces = change in kinetic energy of the body

Work done by the force + Work done by the friction = Kinetic energy at B - kinetic energy at A

- m x g x h + Work done by friction = 0.5 x 120 x (Vb^2 - Va^2)

- 120 x 9.8 x 24 + Work done by friction = 60 x (64 - 625)

- 28224 + Work done by friction = - 33660

Work done by friction = -33660 + 28224 = - 5436 J

4 0

3 years ago

Three 7-ohm resistors are connected in parallel with an ideal 12-volt battery. What is the equivalent resistance of the circuit?

Alika [10]

Answer:

Equivalent Resistance of Resistors in Parallel is

1/R = 1/r1 + 1/r2 .....

1/R = 1/7 + 1/7 + 1/7

R= 7/3

R=2.33ohms

7 0

3 years ago

A car acquires a velocity of 72km/h in 10sec starting from rest .find it's

mina [271]

Distance travelled.

8 0

4 years ago

Work out the current through an electric heater with a power of 1.38kW if it uses the 230V mains supply.

love history [14]

Answer:

I = 6 A

Explanation:

Given that,

Power of an electric heatr, P = 1.38 kW

The voltage of the mains supply, V = 230 V

We need to find the current through the heater. The electric power in terms of voltage and current is given by :

$P=V\times I\\\\I=\dfrac{P}{V}\\\\I=\dfrac{1.38\times 10^3}{230}\\\\I=6\ A$

So, the current through an electric heater is 6 A.

5 0

3 years ago

A canoe floats in a lake. Inside the canoe is a 25 kg steel solid ball. If the ball is thrown into the lake, does the level of t

Rus_ich [418]

Answer:

Explanation:

volume of ball bearing = 4/3 π r³

= 4/3 x 3.14 x 1.5³

= 14.13 cc.

if D be the density of steel , weight of the ball bearing

= 14.13 x D x g

For the first case , water will be displaced to keep it floating

weight of displaced water will be equal to weight of steel

weight of displaced water = 14.13 Dg

mass of displaced water = 14.13 D

volume of displaced water = mass / density of water

= 14.13 D / d ; (where d is density of water) .

Now when the steel ball bearing is dipped in water , it will displace water equal to its volume only and it will be drowned

its volume = 14 .13 cc

14.13 D / d > 14.13 ( because D/d is more than one , since D > d )

volume of water displaced in first case is greater

water level will go up higher in first case .

Hence in the second case water level will go down .

Same will happen in case of 25 kg steel .

4 0

3 years ago