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3 years ago

1. What would cause a wave to travel at a different speed?

Physics

1 answer:

kvv77 [185]3 years ago

3 0

Answer:

1 going from a gas to a liquid

2 longitudinal waves

3 longitudinal waves

4 transverse waves

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5.3 two 30 kg children in a 20 kg cart are stationary at the top of a hill. They start rolling down the 80 m tall hill and they

Makovka662 [10]

Answer:

60008.4 J

Explanation:

The mass of each kid = 30 kg

mass of the cart = 20 kg

The speed of the cart down the hill = 30 km/hr = 30 x 1000/3600 = 8.33 m/s

The height of the hill = 80 m

The potential energy of the boys at the top of the hill = mgh

where

m is the total mass of the kids and the cart = (30 x 2) + 20 = 80 kg

g is the acceleration due to gravity = 9.81 m/s^2

h is their height above the ground = 80 m (on the top of the hill)

substituting, we have

potential energy PE = 80 x 9.81 x 80 = 62784 J

At an instance at the bottom of the hill

their kinetic energy = $\frac{1}{2} mv^2$

where

v is their velocity = 8.33 m/s

m is their total mass = 80 kg

substituting, we have

kinetic energy KE = $\frac{1}{2}*80*8.33^2$ = 2775.6 J

Total work done on the cart is equal to the energy lost by the cart when it reached the bottom of the hill

work done by friction = PE - KE = 62784 - 2775.6 = 60008.4 J

5 0

3 years ago

Refrigerant-134a enters an adiabatic compressor as saturated vapor at -24C and leaves at 0.8 MPa and 60C. When the mass flow r

sergey [27]

Answer:

= 287kW

Explanation:

Knowing the enthalpy data, we have to

$h1=239.16kJ/kg\\h2=296.81kJ/kg$

So,

$E_i_n_p_u_t=mh_1$

Here,

m=mass flow rate

h= Enthalpy of refrigerant at the compressor

Replacing

= 1.2 × 239.16

= 287kW

4 0

3 years ago

Determine the gradient and the co-ordinates of the x and y intercept of line whose equation is 2y + 3x = 1

Savatey [412]

Answer:

The x - intercept is 1/3

The y - intercept is 1/2

The gradient is -3/2

Explanation:

To find the x - intercept of the equation 2y + 3x = 1, we find the value of x when y = 0. So,

2y + 3x = 1

2(0) + 3x = 1

0 + 3x = 1

3x = 1

x = 1/3

So, the x - intercept is 1/3

To find the y - intercept of the equation 2y + 3x = 1, we find the value of y when x = 0. So,

2y + 3x = 1

2y + 3(0) = 1

2y + 0 = 1

2y = 1

y = 1/2

So, the y - intercept is 1/2

To find the gradient of the equation 2y + 3x = 1, we re-write it in gradient intercept form by making y subject of the formula.

So, 2y + 3x = 1

2y = -3x + 1

y = -3x/2 + 1/2

The coefficient of x which equals -3/2 is the gradient.

The gradient is -3/2

4 0

3 years ago

Which of the following types of electromagnetic radiation has the highest energy?

Varvara68 [4.7K]

B. Gamma rays
Gamma rays have highest energy

3 0

3 years ago

A small 175-g ball on the end of a light string is revolving uniformly on a frictionless surface in a horizontal circle of diame

dalvyx [7]

Complete question:

A small 175-g ball on the end of a light string is revolving uniformly on a frictionless surface in a horizontal circle of diameter 1.0 m. The ball makes 2.0 revolutions every 1.0 s. What are the magnitude and direction of the acceleration of the ball?

Answer:

The acceleration of the ball is 78.98 m/s², directed inwards

Explanation:

Given;

mass of the ball, m = 175 g

radius of the circle, r = 0.5 m

angular speed of the ball, ω = 2 rev/s

The magnitude of the centripetal acceleration of the ball is calculated as follows;

$a_c = \omega^2 r\\\\where;\\\omega \ is \ angular \ speed \ in \ rad/s\\\\a_c = (2\ \frac{rev}{s} \times \frac{2\pi \ rad}{1 \ rev} )^2 \times (0.5 \ m)\\\\a_c =78.98 \ m/s^2$

The centripetal acceleration is directed inwards.

8 0

3 years ago