1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
lukranit [14]
3 years ago
15

Suppose that the acceleration of a model rocket is proportional to the difference between 160 ft/sec and the rocket's velocity.

If it is initially at rest and its initial acceleration is 280 ft/sec22, how long will it take to accelerate to 128 ft/s
Physics
1 answer:
Levart [38]3 years ago
5 0

Answer:

Explanation:

Given ,

dv / dt = k ( 160 - v )

dv / ( 160 - v ) = kdt

ln ( 160 - v ) = kt + c , where c is a constant

when t = 0 , v = 0

Putting the values , we have

c = ln 160

ln ( 160 - v ) = kt + ln 160

ln ( 160 - v / 160 ) = kt

(160 - v ) / 160 = e^{kt}

1 - v / 160 = e^{kt }

v / 160 = 1 - e^{kt }

v = 160 ( 1 - e^{kt } )

differentiating ,

dv / dt = - 160k e^{kt }

acceleration a   = - 160k e^{kt }

given when t = 0 , a = 280

280 = - 160 k

k = - 175

a = - 160 x - 175 e^{kt}

a = 28000 e^{kt}

when a = 128  t = ?

128 = 28000 e^{kt}

e^{kt } = .00457

You might be interested in
An engine has an energy input of 125j and 35 j of that energy is transformed into useful energy
Tatiana [17]
The engine's efficiency is (35J)/125J) = 28% .

Do you have a different question to ask ?
5 0
3 years ago
car 2 has a mass of 150 kg and moves westward towards car 3 at a velocity of 2.2 m/s. car 3 has a mass of 265 kg and moves eastw
sergejj [24]

Answer:

The force of car 3 on car 2 ≈ 1810.82 N

Explanation:

The equation for the change in momentum of the two cars are;

Conservation of linear momentum

150( 2.2 - v) = 265(1.5-v)

150 × 2.2 - 265×1.5 = (150+265)v

150 × 2.2 - 265×1.5 = -67.5 = 415×v

∴ v = -67.5/415 = -0.1627 m/s West = 0.1627 m/s East

The impulse of the net force is the amount of momentum change experienced given by the equation;

Impulse force = m \times  v_f - m \times  v_0

Where;

v_f = The final velocity

v_0 = The initial velocity

For the the 265 kg mass, we have;

v_f = 0.1627 m/s

v_0 = 1.5 m/s

Which gives the impulse a s F×Δt =  265×0.1627 - 265×1.5 = -354.38 kg·m/s

The change in kinetic energy of the collision = 1/2×265×(0.1627^2 - 1.5^2) =-294.62 J

Whereby the distance moved in one second is 0.1627 m, we have;

Work done = Force × Distance = Force × 0.1627 = 294.62

Force = 294.62/0.1627 = 1810.82 N.

8 0
3 years ago
At what distance from the centre of the earth its acceleration due to gravity becomes one third only? [Mass and radius of earth
Kipish [7]

Answer:

235

Explanation:

3 0
3 years ago
Read 2 more answers
Robin is standing terrified at the end of a diving board, which is high above the water. If Robin has a mass of 76 kg and is sta
masya89 [10]

Answer:

 Torque = 1191.68 N-m

Explanation:

Given data

mass m = 76 kg

standingdistance r  = 1.6 m

Solution

we get here torque  that si express as

torque  = force × distance ................1

torque  = r × F sin(theta)

and we know that

F = mg   .........2

and g = 9.8 m/s²

put here value in equation 1 we get

Torque = 76 × 1.6 × 9.8 × sin(90)

 Torque = 1191.68 N-m

5 0
3 years ago
A 75 kg soccer player jumps vertically upwards and heads the 0.45 kg ball as it is descending vertically with a speed of 24 m/s.
Vikentia [17]

Answer:

31.66 m/s

Explanation:

mass of player, M = 75 kg

mass of ball, m = 0.45 kg

initial velocity of player, U = + 4 m/s

initial velocity of ball, u = - 24 m/s

Let the final speed of player is V and the ball is v.

use conservation of momentum

Momentum before collision = momentum after collision

75 x 4 - 0.45 x 24 = 75 x V + 0.45 x v

289.2 = 75 V + 0.45 v    .... (1)

As the collision is perfectly elastic, coefficient of restitution,e = 1

So, e=\frac{v_{1}-v_{2}}{u_{2}-u_{1}}

V - v = u - U

V - v = -24 - 4 = - 28

V = v - 28, put this value in equation (1), we get

289.2 = 75 (v - 28) + 045 v

289.2 = 75 v - 2100 + 0.45 v

2389.2 = 75.45 v

v = 31.66 m/s

Thus, the velocity of ball after collision is 31.66 m/.

7 0
3 years ago
Other questions:
  • A fisherman's scale stretches 3.7 cm when a 3.5 kg fish hangs from it. (a) what is the spring constant? n/m (b) what will be the
    8·1 answer
  • When a cup is placed on a table, which force prevents the cup from falling to the ground?
    8·1 answer
  • How was the water filtered to remove debris and living organisms?
    10·2 answers
  • To calibrate the calorimeter electrically, a constant voltage of 3.6 V is applied and a current of 2.6 A flows for a period of 3
    11·1 answer
  • Alex rides her bike at 12.0 km/hr for 2.25 hr. what distance has alex traveled?
    7·1 answer
  • Low-frequency red light is used in dark rooms because it does not expose the film. This is because the red light has a low
    14·2 answers
  • 1. Calculate the average velocity of the following trip. You walk to Pershing Square 58
    10·1 answer
  • In Converging and Diverging lenses all real images are
    7·2 answers
  • Of the 5000 species of mammals, 250 species are carnivorous. What is the ratio of carnivorous to mammals?
    8·1 answer
  • Question 9 of 10
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!