Which is a key criterion for the design of an automobile bumper?

NEES HELP!!!!

OLga [1]

Answer:

Doppler Theory

Explanation:

it's a theory regarding the change in wave frequency during the relative motion between a wave source and its observer.

6 0

2 years ago

Discuss whether any work is being done by each of the following agents and, if so, whether the work is positive or negative: (a)

Aleks04 [339]

Answer:

a) As the chicken is still, the displacement is zero, which implies that the work is zero.

b) as the person is still there is no displacement therefore the work is zero

c) Lagraua applies a vertical force and the displacement is vertical, therefore the Work is positive

d) the force of gravity is directed downwards and the displacement is upwards, therefore the angle between it is 180º and the 180º fly is -1. Consequently the lock is negative

e) when the person meticulously feels the upward force and the displacement is downward, therefore the work is negative

Explanation:

Work is defined by the expression

W = F. r

bold letters indicate vectors, we can write this expression as a module

W= F r cos θ

where is at the angle between force and displacement.

Let's apply this expression to the different cases

a) As the chicken is still, the displacement is zero, which implies that the work is zero.

b) as the person is still there is no displacement therefore the work is zero

c) Lagraua applies a vertical force and the displacement is vertical, therefore the Work is positive

d) the force of gravity is directed downwards and the displacement is upwards, therefore the angle between it is 180º and the 180º fly is -1. Consequently the lock is negative

e) when the person meticulously feels the upward force and the displacement is downward, therefore the work is negative

7 0

3 years ago

A combustion reaction usually gives off heat and light is it true or false

yanalaym [24]

The answer is true I think

3 0

3 years ago

a uniform metre rule is pivoted at its centre and weights of 5 N and 12 N are hung at the 3 cm and 5 cm marks respectively. how

schepotkina [342]

In order to balance the stick on the pivot, the total "moments" must be equal on both sides. A "moment" is (a weight) x (its distance from the center).

for the 5N weight: Moment = (5N) x (3 cm) = 15 N-cm

for the 12N weight: Moment = (12N) x (5 cm) = 60 N-cm

Sum of the moments trying to pull the stick down on that side = 75 N-cm

Whatever we hang on the other side has to provide a moment of 75 N-cm in the other direction. We have a 25N weight. Where should we hang it ?

(25N) x (distance from the pivot) = 75 N-cm

Distance from the pivot = (75 N-cm) / (25 N)

<em>Distance from the pivot = 3 cm </em>

8 0

3 years ago

A) Determine the x and y-components of the ball's velocity at t = 0.0s, 2.0, 3.0 secs.

malfutka [58]

The kinematic relationships we can find the position, acceleration and launch angle of the body on the planet Exidor.

a) the position are

time (s) x (m) y(m)

0 0 0

2.0 3.6 1.2

3.0 5.4 0.9

b) The aceleration is g = 0.6 m / s²

c) The launch angle θ = 33.7º

given parameters

the initial velocity of the body vₓ = 1.8m / s and v_y = 1.2 m / s

the movement times t = 1.0s, 2.0s and 3.0 s

to find

a) position

b) acceleration

c) launch angle

Projectile launch is an application of kinematics to the movement of the body in two dimensions where there is no acceleration on the x axis and the y axis has the planet's gravity acceleration

b) To calculate the acceleration of the plant acting on the y-axis, we use that the vertical velocity of the body at the highest point is zero.

v_y = v_{oy} - g t

where v and v({oy} are the velocities of the body, g the acceleration of the planet's gravity and t the time

0 = v_{oy} - gt

g = v_{oy} / t

from the graph we observe that the highest point occurs for t = 2.0 s

g = 1.2 / 2.0

g = 0.6 m / s²

a) The position is requested for several times

X axis

in this axis there is no acceleration so we can use the uniform motion relationships

vₓ = x / t

x = vₓ t

where x is the position, vx is the velocity and t is the time

we calculate for the time

t = 0.0 s

x₀ = 0

t = 2.0 s

x₂ = 1.8 2

x₂ = 3.6 m

t = 3.0 s

x₃ = 1.8 3

x₃ = 5.4 m

Y axis

In this axis there is the acceleration of the planet, let us use for the position the relation

y = v_{oy} t - ½ g t²

t = 0.0 s

y₀ = 0

y₀ = 0 m

t = 2.0 s

y₂ = 1.2 2 - ½ 0.6 2²

y₂ = 1.2 m

t = 3.0 s

y₃ = 1.2 3 - ½ 0.6 3²

y₃ = 0.9 m

c) the launch angle use the trigonometry relation

tan θ = $\frac{v_y}{v_x}$

θ = tan⁻¹ $\frac{v_y}{v_x}$

θ = tan⁻¹ $\frac{1.2}{1.8}$

θ = 33.7º

measured counterclockwise from the positive side of the x-axis

With the kinematic relationships we can find the position, acceleration and launch angle of the body on the planet Exidor.

a) the position are

time (s) x (m) y(m)

0 0 0

2.0 3.6 1.2

3.0 5.4 0.9

b) The aceleration is g = 0.6 m / s²

c) The launch angle θ = 33.7ºto)

learn more about projectile launch here:

brainly.com/question/10903823

4 0

2 years ago