What is the momentum of a 0.5 kg ball which is thrown at 20 m/s?

4. An electric iron has a

Licemer1 [7]

Answer:

4.

a) W = 750 J

b) W = 2250 J

c) t = 2 sec

5. Answered in explanation

Explanation:

4.

The formula of power is given as:

P = W/t

where,

P = Power

W = Work Done

t = Time Taken

a)

Here,

P = 750 W

t = 1 sec

W = ?

Therefore,

750 W = W/1 sec

W = 750 J

b)

Here,

P = 750 W

t = 3 sec

W = ?

Therefore,

750 W = W/3 sec

W = (750 W)(3 sec)

W = 2250 J

c)

Here,

P = 750 W

t = ?

W = 1500 J

Therefore,

750 W = 1500 J/t

t = 1500 J/750 W

t = 2 sec

5.

According to Kinetic Particle Theory, the molecules are tightly packed with each other, by strong inter-molecular forces and they can only vibrate at their position. While, molecules or particles in liquids have lesser attractive forces among them. They can move in layers and can take the shape of any container. This is the reason why solid has a definite shape and liquid has none.

6 0

2 years ago

If the distance between the center of two objects is quadrupled. The gravitational

Juliette [100K]

Answer:

F' = F/16

Explanation:

The gravitational force between masses is given by :

$F=G\dfrac{m_1m_2}{r^2}$

If the distance between the center of two objects is quadrupled, r' = 4r

New force will be :

$F'=G\dfrac{m_1m_2}{r'^2}\\\\F'=G\dfrac{m_1m_2}{(4r)^2}\\\\F'=\dfrac{Gm_1m_2}{16r^2}\\\\F'=\dfrac{1}{16}\times \dfrac{Gm_1m_2}{r^2}\\\\F'=\dfrac{F}{16}$

So, the new force will change by a factor of 16.

6 0

2 years ago

Plaease help me with thesse four 40 points

Zielflug [23.3K]

Answer:

For the first one c is the answer

For the second one c is also the answer

For the third one is b

Explanation:

I took that

3 0

2 years ago

David wants to experiment with the device, so he connects an ammeter into the circuit and measures 11.5 AA when the device is co

Mandarinka [93]

Answer:

2.42hours

Explanation:

To calculate the time taken to boil the cup of water, we will use the formula

Q = It where

Q is the total energy required to boil the water = 100KJ = 100,000Joules

I is the current = 11.5A

t is the time taken to boil the water

t = Q/I

t = 100,000/11.5

t = 8695.65seconds

t = 2.42hours

4 0

2 years ago

An aircraft is in level flight at 225 km/hr through air at standard conditions. The lift coefficient at this speed is 0.45 and t

mojhsa [17]

Answer:

- the effective lift area for the aircraft is 8.30 m²

- the required engine thrust is 1275 N

- required power is 79.7 kW

Explanation:

Given the data in the question;

Speed V = 225 km/hr = 62.5 m/s

The lift coefficient CL = 0.45

drag coefficient CD = 0.065

mass = 900 kg

g = 9.81 m/s²

a) the effective lift area for the aircraft

we know that for a steady level flight, weight = lift and thrust = drag

Using the equation for the lift force

F $_L$ = C $_L$ $\frac{1}{2}$ ρV²A = W

we substitute

0.45 × $\frac{1}{2}$ × 1.21 × ( 62.5 )² × A = ( 900 × 9.81 )

1081.05 × A = 8829

A = 8829 / 1081.05

A = 8.30 m²

Therefore, the effective lift area for the aircraft is 8.30 m²

b) the required engine thrust and power to maintain level flight.

we use the expression for drag force

F $_D$ = T = C $_D$ $\frac{1}{2}$ ρV²A

we substitute

= 0.065 × $\frac{1}{2}$ × 1.21 × ( 62.5 )² × 8.30

T = 1275 N

Since drag and thrust force are the same,

Therefore, the required engine thrust is 1275 N

Power required;

P = TV

p = 1275 × 62.5

p = 79687.5 W

p = ( 79687.5 / 1000 )kW

p = 79.7 kW

Therefore, required power is 79.7 kW

8 0

2 years ago