I forgot this someone help

Darina [25.2K]

Physical properties change

hope that helps

4 0

3 years ago

Susan is running to the right, in the +x-direction, at 2 m/s. A bird flies past her, traveling to the left at 10 m/s. What is th

anastassius [24]

The concept of relative velocity can be found the speed of the bird respecting susan v = -12 m / s. The negative sign indicates that the bird is approaching susan

given parameter

the speeds of Susam and the bird

to find

the relative speed between Susan and the bird

Velocity is a vector unit, therefore, in addition to magnitude, it has direction and sense, therefore, to make the sum of the same quantities, vector relations must be used

v₁ = v₂ + v₃

where v₁, v₂ and v₃ are velocity and the bold letters indicate vectors

in this case Susan and the bird go on the x axis therefore the algebra is reduced to the algebraic sum. We will assume that the positive direction is to the right of the x-axis, consequently the velocities are:

Susan v_{st} = 2 m / s

Bird v_{bt} = - 10 m / s

The relative velocity is the vector sum of the velocities of the bodies, one way to perform this sum is by using subscripts

v_{pt} = v_{ps} + v_{st}

Where v_{ps} is the speed of the bird relative to susan, v_{st} is the speed of susan relative to the ground, and v_{pt} is the speed of the bird relative to the ground.

v_{ps} = v_{pt} - v_{st}

v_{ps} = -10 - 2

v_{ps} = - 12 m / s

Using the concept of relative velocity, the velocity of the bird respecting susan v = -12 m/s can be found. The negative sign indicates that the bird is approaching susab.

Learn more about relative velocity here:

brainly.com/question/19260269

5 0

3 years ago

1.A steel cable is attached to a ring on the top of a street light. The weight of the street light is W . The other end of the c

mixer [17]

Answer:

a) Please find attached, the vector diagram regarding the question

i) The direction of the sum of the vectors is the negative direction of the vertical or y-axis

ii) The scale is 1 mm = 1 N

W = 25 N

The mass of W is approximately 2.55 kg

Explanation:

The given parameters are;

The angle of inclination of the cable to the vertical = 55°

The tension in the cable = 43.6 N

a) i) The direction of the vector sum of the two forces is given as the resultant of the two forces;

The component of the tension in the chain is given as follows;

Tension in the horizontal chain = x $\mathbf{ \hat i}$

The resolved force in the cable is given as follows;

Given that the force is acting upwards along the cable

F = 43.6 × -sin(55°) $\mathbf{ \hat i}$ + 43.6 × cos(55°) $\mathbf{ \hat j}$

F ≈ -35.72 $\mathbf{ \hat i}$ + 25 $\mathbf{ \hat j}$

Therefore, from ∑Fₓ = 0 and ∑F $_y$ = 0, since the horizontal force in the chain will balance the horizontal component of the tension in the cable, there will be no net horizontal force and the resultant force will have a direction of the vertical y-axis

ii)

Given that ∑F = 0, we have;

The tension in the cable is an horizontal force, therefore, we have;

∑Fₓ = 0

The tension in the horizontal chain + The horizontal component of the cable = 0

The tension in the horizontal chain - 35.72 N = 0

∴ The tension in the horizontal chain = 35.72 N

The weight of the street light + The vertical component of the tension = 0

The weight of the street light + 25 N = 0

Therefore;

The weight of the street light W = -25 N

The scale of the vector diagram used is 1 mm = 1 N

W = -25 N

The mass of the street light = Weight of the street light/(Acceleration due to gravity)

The mass of the street light = 25 N/(9.81 m/s²) ≈ 2.55 kg

7 0

3 years ago

A child holds onto a string attached to a toy boat and exerts a force of 7.5 N to pull the boat a distance of 9.2 m a long a str

soldi70 [24.7K]

The work that need to do is 66.24 J.

<h3>Explanation :</h3>

Hello guys, before we can count how much the work that needed to pull the toy, we should know how formula to count it first. Because the movement is with the angle, so the formula is :

$\boxed {\bold {W = F \times s \times \cos(\theta)}}$