All categories

3 years ago

A 4.0 kg model rocket is launched, shooting 50.0 g of burned fuel from its exhaust at

Physics

1 answer:

Anettt [7]3 years ago

3 0

The velocity of the rocket is 7.8 m/s

Explanation:

We can solve the problem by using the law of conservation of momentum: in fact, in absence of external forces, the total momentum of the rocket+fuel system must be conserved.

Before the launch, the total momentum of the system is zero, since the rocket and the fuel are at rest:

$p=0$

After the launch, the total momentum is

$p=MV+mv$

where

M = 4.0 kg is the mass of the rocket

V is the velocity of the rocket

m = 50.0 g = 0.050 kg is the mass of the fuel ejected

v = -625 m/s is the velocity of the fuel (taking "backward" as negative direction)

Since the total momentum is conserved, we have

$0=MV+mv$

So we can solve the equation to find V, the velocity of the rocket:

$V=-\frac{mv}{M}=-\frac{(0.050)(625)}{4.0}=+7.8 m/s$

And the positive sign means the rocket moves forward.

Learn more about momentum:

brainly.com/question/7973509

brainly.com/question/6573742

brainly.com/question/2370982

brainly.com/question/9484203

#LearnwithBrainly

You might be interested in

Why does the car stop? Where did the energy go?

Viefleur [7K]

Answer:

Because you hit the break?

8 0

3 years ago

2. Two toy cars are involved in a race. Car A has mass m while car B has mass 2m. a. The two cars have the same force applied to

ArbitrLikvidat [17]

Answer:

a) The kinetic energy of the two cars is the same

the moment of car 2 is greater than the moment of car 1

b) the kinetic energy of car 1 is greater than that of car 2

the moment of the two cars is the same

Explanation:

a) to know the kinetic energy of each car, we must find the speed, use Newton's second law to find the acceleration

Car 1

F = m a

a = F / m

Let's use kinematics to find the velocity after x = 1 m

v² = v₀² + 2 a x

The initial speed is zero

v = √ (2 F/m x)

For the distance of x = 1 m

v₁ = √ (2 F / m)

Car 2

F = 2m a

a = F / 2m

v² = 2 a x

v = √ (F/m x)

For x = 1 m

v₂ = √(F / m)

Let's calculate the kinetic energy of each car

Car 1

K₁ = ½ m v₁²

K₁ = ½ m 2F / m

K₁ = F

Car 2

K₂ = ½ 2m v₂²

K₂ = ½ 2m F / m

K₂ = F

The kinetic energy of the two cars is the same

Let's calculate the moment

Car 1

P₁ = m v₁

P₁ = m √ (2F / m)

Car 2

P₂ = 2m v²

P₂ = 2m √(F / m)

We see that the moment of car 2 is greater than the moment of car 1

b) in this part the force is applied by t = 10 s

Acceleration is the same, let's find the speed

Car1

v = v₀ + a t

v = F / m t

v₁ = F / m 10

Car 2

v₂ = F / 2m 10

v₂ = F / m 5

Let's calculate the kinetic energy of each car

Car 1

K₁ = ½ m v₁²

K₁ = ½ m (F / m 10)²

K₁ = 50 F² / m

Car2

K₂ = ½ 2m v₂²

K₂ = m (F / m 5)²

K₂ = 25 F² / m

In this case we see that the kinetic energy of car 1 is greater than that of car 2

Let's calculate the moment

Car 1

P₁ = m v₁

P₁ = m F / m 10

P₁ = 10 F

Car 2

P₂ = 2m v₂

P₂ = 2m F / m 5

P₂ = 10 F

In this case the moment of the two cars is the same

7 0

3 years ago

A spring 1.50 m long with force constant 448 N/m is hung from the ceiling of an elevator, and a block of mass 10.9 kg is attache

GuDViN [60]

Answer:

Explanation:

Let the extension in the spring be x .

restoring force = weight of block

kx = mg

x = $\frac{10.9\times9.8}{448}$

= 23.84 cm

b )

When the elevator is going upwards

Restoring force = mg + ma

k x₁ = 10.9 ( 9.8 + 1.89 )

x₁ = 28.44 cm

( y coordinate will be - ( 28.44 - 23.84 ) = - 4.6 cm )

c ) When the cable snaps , both elevator and block undergo free fall . In this case apparent g = 0

Since the spring is stretched by 28.44 cm , a restoring force continues to act on the block which is equal to

.2844 x 448

= 127.41 N

So a net acceleration a will act on the block

a = 127.41 / 10.9

= 11.68 m / s²

The block will undergo SHM with amplitude equal to 28.44 cm .

3 0

3 years ago

The speed of the wave depends on what?

kolbaska11 [484]

The speed of a mechanical wave depends on the mechanical properties
of the medium through which the wave is traveling.

The speed of an electromagnetic wave depends on the electrical properties
of the medium through which the wave is traveling.

It's pretty well unanimous for choice <em>A</em> .

4 0

3 years ago

there are two slides at the park between which you are deciding. Both start at the height of 6 meter. One is short and Steve whi

kumpel [21]

It doesn't matter. If the slides are truly frictionless, then
your kinetic energy at the bottom will be equal to the
potential energy you had at the top, no matter what kind
of route you took getting down.
___________________________

The only way I can think of that it would make a difference
would be if the shallow slide were REALLY REALLY long,
and you didn't have anything to eat all the way down.
Then you might lose some weight while you're on the slide,
and your mass might be less at the bottom than it was at the
top. Then, in order to have the same kinetic energy at the
bottom, you'd need to be going a little bit faster.

But if it takes less than, say, two or three days, to go down the
long, shallow slide, then this effect would probably be too small
to make any difference.

6 0

3 years ago