Number 5 pls I really need help

An object of mass m is sliding with speed vi at some instant across a level tabletop, with which its coefficient of kinetic fric

gogolik [260]

Answer:

√2µgd = vi

Explanation:

Given that the mass of object is m

Sliding speed of object is vi

coefficient of kinetic friction is µ

Distance covered is d

Final speed, vf is 0

Equation to apply will be;

v²f=v²i-2µgd where g is acceleration due to gravity

v²f+2µgd=v²i----------------------but v²f = 0

2µgd=v²i

√2µgd = vi

5 0

3 years ago

Which statement about energy transformations is not true?

frutty [35]

Answer:

C

Explanation:

Let's consider the conservation of energy

Energy can not be destroyed or created energy can be transferred one form energy to a another form of energy.

(A) Then all form of energy can be transfer into any form of energy . There for all forms of energy can be transformed to thermal energy

(B) This is the law of conservation of energy

(C)Potential chemical energy can be transferred into any form of energy. It's not only to kinetic energy

(D) Some amount of thermal energy always released when it's transferred energy due to reaction forces or frictional forces.

3 0

3 years ago

Four copper wires of equal length are connected in series. Their cross-sectional areas are 1.6 cm2 , 1.2 cm2 , 4.4 cm2 , and 7 c

EleoNora [17]

Answer:

63.8 V

Explanation:

We are given that

$A_1=1.6 cm^2=1.6\times 10^{-4} m^2$

$1 cm^2=10^{-4} m^2$

$A_2=1.2 cm^2=1.2\times 10^{-4} m^2$

$A_3=4.4 cm^2=4.4\times 10^{-4} m^2$

$A_4=7 cm^2=7\times 10^{-4} m^2$

Potential difference,V=140 V

We know that

$R=\frac{\rho l}{A}$

According to question

$l_1=l_2=l_3=l_4=l$

In series

$R=R_1+R_2+R_3+R_4$

$R=\rho l(\frac{1}{A_1}+\frac{1}{A_2}+\frac{1}{A_3}+\frac{1}{A_4})$

$R=\rho l(\frac{1}{1.6\times 10^{-4}}+\frac{1}{1.2\times 10^{-4}}+\frac{1}{4.4\times 10^{-4}}+\frac{1}{7\times 10^{-4}})$

$R=\rho l(18284.6)$

$I=\frac{V}{R}=\frac{140}{\rho l\times 18284.6}$

Potential across 1.2 square cm= $V_1=IR_1=\frac{140}{\rho l\times 18284.6}\times \rho l(\frac{1}{1.2\times 10^{-4}}=63.8 V$

Hence, the voltage across the 1.2 square cm wire=63.8 V

3 0

3 years ago

A 42.6kg lamp is hanging from wires as shown in figure.The ring has negligible mass. Find tensionsT1, T2,T3 if the object is in

IRISSAK [1]

Answer:

T1 = 417.48N

T2 = 361.54N

T3 = 208.74N

Explanation:

Using the sin rule to fine the tension in the strings;

Given

amass = 42.6kg

Weight = 42.6 * 9.8 = 417.48N

The third angle will be 180-(60+30)= 90 degrees

Using the sine rule

W/Sin 90 = T3/sin 30 = T2/sin 60

Get T3;

W/Sin 90 = T3/sin 30

417.48/1 = T3/sin30

T3 = 417.48sin30

T3 = 417.48(0.5)

T3 = 208.74N

Also;

W/sin90 = T2/sin 60

417.48/1 = T2/sin60

T2 = 417.48sin60

T2 = 417.48(0.8660)

T2 = 361.54N

The Tension T1 = Weight of the object = 417.48N

8 0

3 years ago

What is the frequency of a wave with speed 3m/s and wavelength 6m?

Korolek [52]

The frequency of the radio wave is

1

×

10

8

H

z

Explanation:

Let's use the this formula:

C

=

λ

×

v

C represents the speed of light, which has a value of approximately

3.00

×

10

8

m

s

λ

represents the wavelength and the units should be in meters.

v represents the frequency, which should have units of

H

z

or

s

−

1

. Hz is hertz or reciprocal seconds.

Now let's rearrange the equation to solve for v:

C

λ

=

v

=

3.00

×

10

8

m

s

/

(

3

m

)

=

1

×

10

8

s

−

1The frequency of the radio wave is

1

×

10

8

H

z

Explanation:

Let's use the this formula:

C

=

λ

×

v

C represents the speed of light, which has a value of approximately

3.00

×

10

8

m

s

λ

represents the wavelength and the units should be in meters.

v represents the frequency, which should have units of

H

z

or

s

−

1

. Hz is hertz or reciprocal seconds.

Now let's rearrange the equation to solve for v:

C

λ

=

v

=

3.00

×

10

8

m

s

/

(

3

m

)

=

1

×

10

8

s

−

1The frequency of the radio wave is

1

×

10

8

H

z

Explanation:

Let's use the this formula:

C

=

λ

×

v

C represents the speed of light, which has a value of approximately

3.00

×

10

8

m

s

λ

represents the wavelength and the units should be in meters.

v represents the frequency, which should have units of

H

z

or

s

−

1

. Hz is hertz or reciprocal seconds.

Now let's rearrange the equation to solve for v:

C

λ

=

v

=

3.00

×

10

8

m

s

/

(

3

m

)

=

1

×

10

8

s

−

1The frequency of the radio wave is

1

×

10

8

H

z

Explanation:

Let's use the this formula:

C

=

λ

×

v

C represents the speed of light, which has a value of approximately

3.00

×

10

8

m

s

λ

represents the wavelength and the units should be in meters.

v represents the frequency, which should have units of

H

z

or

s

−

1

. Hz is hertz or reciprocal seconds.

Now let's rearrange the equation to solve for v:

C

λ

=

v

=

3.00

×

10

8

m

s

/

(

3

m

)

=

1

×

10

8

s

−

1

3 0

2 years ago