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Mandarinka [93]

3 years ago

6

5. A family of ducks is swimming in a pond at a speed of 3 m/s when a gust of wind hits them. By the time they reach the other s

ide of the lack, the ducks are moving at a speed of 7 m/s. How long did it take for them to cross the lake if they accererated at a rate of 1 m/s2

1 answer:

ella [17]3 years ago

6 0

Answer:

The time taken by the duck to cross the lake is, t= 4 s

Explanation:

Given data,

The initial speed of the ducks, u = 3 m/s

The final speed of the ducks, v = 7 m/s

The acceleration of the duck, a = 1 m/s²

The formula for the acceleration is,

a = (v - u) / t

∴ t = (v - u) / a

Substituting the given values in the above equation,

t = (7 - 3) / 1

= 4 s

Hence, the time taken by the duck to cross the lake is, t= 4 s

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A bus accelerates to 60 m/s to the east in 10 s. What is the buses acceleration? 2. A car traveling at 10.0 m/s to the west acce

professor190 [17]

Answers:

1) $a=6\frac{m}{s^{2}}$

2) $t=8s$

Explanation:

1) Acceleration $a$ is defined as the variation of Velocity $V$ in time $t$ :

$a=\frac{V}{t}$ (1)

A body also has acceleration when it changes its direction.

In this case we have a bus with a velocity of 60m/s to the east, that accelerates in a time 10s. So, we have to find the bus's acceleration:

$a=\frac{60m/s}{10s}$ (2)

$a=6m/s^{2}$ (3) This is the bus's accelerration

2) Now we have a car that accelerates $2m/s^{2}$ to the west in order to reach a speed of $16m/s$ in the same direction, and we have to find the time $t$ it takes to the car to reach that velocity.

Therefore we have to find $t$ from (1):

$t=\frac{V}{a}$ (4)

$t=\frac{16m/s}{2m/s^{2}}$ (5)

Finally:

$t=8s$ (6)

3 0

3 years ago

A 10 kg mass car initially at rest on a horizontal track is pushed by a horizontal force of 10 N magnitude. If we neglect the fr

vlada-n [284]

Answer:

50 m

Explanation:

F = ma

10 N = (10 kg) a

a = 1 m/s²

Given:

v₀ = 0 m/s

a = 1 m/s²

t = 10 s

Find: Δx

Δx = v₀ t + ½ at²

Δx = (0 m/s) (10 s) + ½ (1 m/s²) (10 s)²

Δx = 50 m

5 0

2 years ago

A 13 kg hanging sculpture is suspended by a 95-cm-long, 5.0 g steel wire. When the wind blows hard, the wire hums at its fundame

Artyom0805 [142]

Answer:

$f=81.96 \ Hz$

Explanation:

Givens

$L=95cm$

$m_{sculpture} =13kg$

$m_{wire}=5g$

The frequency is defined by

$f=\frac{v}{\lambda}$

Where $v$ is the speed of the wave in the string and $\lambda$ is its wave length.

The wave length is defined as $\lambda = 2L = 2(0.95m)=1.9m$

Now, to find the speed, we need the tension of the wire and its linear mass density

$v=\sqrt{\frac{T}{\mu} }$

Where $\mu=\frac{0.005kg}{0.95m}= 5.26 \times 10^{-3}$ and the tension is defined as $T=m_{sculpture} g=13kg(9.81 m/s^{2} )=127.53N$

Replacing this value, the speed is

$v=\sqrt{\frac{127.53N}{5.26 \times 10^{-3} } }=155.71 m/s$

Then, we replace the speed and the wave length in the first equation

$f=\frac{v}{\lambda}\\f=\frac{155.71 m/s}{1.9m}\\ f=81.96Hz$

Therefore, the frequency is $f=81.96 \ Hz$

3 0

2 years ago

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asambeis [7]

Answer:

22Volts

Explanation:

The pd at the terminal is known as the emf

Since there are Ten 2.2V cells

Terminal voltage = number of cells * pd of one cell

Terminal voltage = 10 * 2.2

Terminal voltage = 22V

Hence the pd at the battery terminals is 22Volts

4 0

2 years ago

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topjm [15]

When light passes through one transparent medium to another transperent medium it bends and that beding of light is know as refraction of light !

8 0

2 years ago

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