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pantera1 [17]
3 years ago
6

A railroad car of mass 2.50∙10^4 kg is moving at a speed of 4.00 m/s. It collides and couples with three other coupled railroad

cars, each of the same mass as the single car and moving in the same direction with an initial speed of 2.00 m/s.
(a)What is the speed of the four cars after the collision?
(b)How much kinetic energy is lost in the collision? Where does this energy go?
Physics
1 answer:
Vinvika [58]3 years ago
8 0

Answer:

a) v = 1.00 m/s

b) ΔKE = 150 kJ

Lost  energy makes heat, noise, vibration in the system

Explanation:

conservation of momentum

let m be the mass of one car

m(4.00) + 3m(0) = 4mv

v = 1.00 m/s

ΔKE = ½m(4.00)² + ½(3m)(0.00)² - ½(4m)(1.00)²

ΔKE = 8m + 0m - 2m = 6m J

ΔKE = 6(2.50e4) = 150 kJ

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6. A 145-g baseball moving 30.5 m/s strikes a stationary 5.75-kg brick resting on small rollers so it moves without significant
Sindrei [870]

Answer:

Explanation:

a )

momentum of baseball before collision

mass x velocity

= .145 x 30.5

= 4.4225 kg m /s

momentum of brick after collision

= 5.75 x 1.1

= 6.325 kg m/s

Applying conservation of momentum

4.4225 + 0 = .145 x v + 6.325 , v is velocity of baseball after collision.

v = - 13.12 m / s

b )

kinetic energy of baseball  before collision = 1/2 mv²

= .5 x .145 x 30.5²

= 67.44 J

Total kinetic energy before collision = 67.44 J

c )

kinetic energy of baseball after collision = 1/2 x .145 x 13.12²

= 12.48 J .

 kinetic energy of brick after collision

= .5 x 5.75 x 1.1²

= 3.48 J

Total kinetic energy after collision

= 15.96 J

3 0
4 years ago
What is the period of a pendulum that takes 5 seconds to make a complete back and forth vibration
dezoksy [38]

Answer:

5s

Explanation:

-A period is the time it takes to make one full back-and-forth swing.

-A period is calculated as the time taken for a complete swing divided by one cycle:

T=t/1c\\\\=5s/1\\\\=5s

Hence, the period of the pendulum is 5s

8 0
4 years ago
A 4.0 kg mass is attached to a spring whose spring constant is 950 N/m. It oscillates with an amplitude of 0.12 m. What is the m
Fudgin [204]

Answer:

velocity = 2.62m/s

Explanation:

950= (4 x A)/0.12

950 x 0.12 = 4 x A

114 = 4 x A

A = 114/4

A = 28.5m/s²

  • U²=2as
  • U² = 2 x 28.5 x 0.12
  • U² = 6.84
  • U = √6.84
  • U = 2.62m/s
3 0
3 years ago
A constant current is sent through a helical coil. the coil
marissa [1.9K]

Answer:

A. Tends to get shorter.

Explanation:

When a constant current is sent through a helical coil, then currents are different turns will be equal as well as in the same direction. As currents in same direction attract each other, hence coil tends to get shorter.

5 0
3 years ago
What type of simple machine is an electric fan?
GrogVix [38]

Answer:

An electric fan is considered to be a mixture of several simple machines. It includes the Wheel and Axle type, wedges, and the Inclined plane types. The blades of an electric fan are the inclined planes and the wedges.

5 0
3 years ago
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