1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
NemiM [27]
3 years ago
13

A car accelerates in the +x direction from rest with a constant acceleration of a1 = 1.76 m/s2 for t1 = 20 s. At that point the

driver notices a tree limb that has fallen on the road and brakes hard for t2 = 5 s with a constant acceleration of a2 = -5.93 m/s2.Write an expression for the car's speed just before the driver begins braking, v1.If the limb is on the road at a distance of 550 meters from where the car began its initial acceleration, will the car hit the limb?
Physics
1 answer:
Ludmilka [50]3 years ago
5 0

Answer:

<em>1) an expression for the car's speed is given as </em>

<em>v = u + at</em>

<em>where </em>

<em>v is the car's speed</em>

<em>u is the initial speed of the car </em>

<em>a is the car's acceleration</em>

<em>t is the time spent accelerating</em>

<em>2) The car does not hit the tree limb</em>

Explanation:

The initial velocity of the car = 0 m/s  (since it accelerates from rest)

acceleration of the car = 1.76 m/s

time spent accelerating = 20 s

For the car's speed just before the driver begins braking, we use the expression

<em>v = u + at</em>

where v is the final speed of the car just before the driver begins braking

u is the initial velocity with which the car starts moving

a is the acceleration of the car

t is the time spent accelerating from u to v

substituting values, we have

v = 0 + 1.76(20)

v = 0 + 35.2

the car's speed v =<em> 35.2 m/s</em>

In this time the car accelerates, the car moves a distance given by

s = ut + \frac{1}{2}at^2

where s is the distance covered in this time

u is the initial speed of the vehicle

a is the acceleration

t is the time taken

substituting, we have

s = 0(20) + \frac{1}{2}(1.76)20^{2}

s = 0 + 352

distance s = <em>352 m</em>

When the driver brakes, we have

time spent braking = 5 s

acceleration = -5.93 m/s

and the distance to the limb = 550 m from where the car begun

to get the distance covered in this period, we use the expression

s = ut + \frac{1}{2}at^2

where s is the distance traveled at this time

u is the speed of the car before it starts braking = 35.2 m/s

a is the acceleration at this point

t is the time taken to decelerate to a stop

substituting values, we have

s = 35.2(5) + \frac{1}{2}(-5.93 x 5^2)

s = 176 - 74.125

s = <em>101.88 m</em>

Total distance moved by the car = 352 m + 101.88 m = <em>453.88 m</em>

Since the total distance traveled by the car is less than the distance from the starting point to the place where the tree limb is, the car does not hit the tree limb.

You might be interested in
Use this free body diagram to help you find the magnitude of the force F2 needed to keep this block in static equilibrium. WILL
oksian1 [2.3K]
Static equilibrium means that all forces are equal, so make this easiest you want to break F1 into it's horizontal and vertical components. As there are no other forces acting in the horizontal, we know the horizontal component of F1 is 40N. This allows the vertical component to be found using pythagorus theorem. After finding the vertical and horizontal components, you just have to add the vertical components to find the difference between the up and down.

4 0
3 years ago
A baseball with a mass of 0.3kg is thrown into the air with a speed of 50 m/s and is at a height of 10m above. What is the speed
makkiz [27]

a una velocidad de

22 m/s, quien lo golpea y devuelve en la misma

dirección con una velocidad de 14 m/s. Si el

tiempo de contacto del balón con la jugadora es

de 0,03 s, ¿con qué fuerza golpeó la jugadora el

balón?

21 Una bala de 0,8 g, está en la recámara de un rifl e

cuando se g

6 0
3 years ago
Zoning laws establish _______. a. what types of buildings can be built in an area b. the uses an area of land can be put to c. w
fiasKO [112]

Answer:

Zoning laws establish b. the uses an area of land can be put to.

5 0
3 years ago
Read 2 more answers
Based on the law of conservation of energy, how can we reasonably improve a machine’s ability to do work?
bagirrra123 [75]
Reduce friction because friction just makes things harder
5 0
3 years ago
Read 2 more answers
Find the equivalent resistance, current, and voltage across each resistor when the specified resistors are connected across a 20
timama [110]

Answer:

Explanation:

The question is incomplete. Here is the complete question.

"Find the equivalent resistance, the current supplied by the battery and the current through each resistor when the specified resistors are connected across a 20-V battery. Part (a) uses two resistors with resistance values that can be set with the animation sliders, and you can use the animation to verify your calculation. In part (b), three resistors are specified. (a) Two resistors are connected in series across a 20-V battery. Let R1 = 1 Ω and R2 = 2 Ω. Rea = (b) Add a third resistor to the circuit in series. Let R1 = 1 Ω, R2 = 2 Ω, and R3 = 3 Ω"

Using ohms law formula to solve the problem

E = IRt

E is the supply voltage

I is the total current

Rt is the total equivalent resistant.

a) Given two resistances

R1 = 1ohms and R2 = 2ohms

If the resistors are Connected in series across a 20V supply voltage,

-Equivalent resistance = R1+R2

= 1ohms + 2ohms

= 3ohms

- In a series connected circuit, same current flows through the resistors.

Using the formula E = IRt

I = E/Rt

I = 20/3

I = 6.67A

The current in both resistors is 6.67A

- Different voltage flows across a series connected circuit.

Using the formula V = IR

V is the voltage across each resistor

I is the current in each resistor

For 1ohms resistor,

V = 6.67×1

V = 6.67Volts

For 2ohms resistor

V = 6.67×2

V = 13.34Volts

b) If the resistors are three

R1 = 1ohms, R2 = 2ohms R3 = 3ohms

- Total equivalent resistance = 1+2+3

= 6ohms

- Current in each resistor I = E/Rt

I = 20/6

I = 3.33A

Since the same current flows through the resistors, the current across each of them is 3.33A

- Voltage across them is calculated as shown:

V = IR

For 1ohm resistor

V = 3.33×1

V = 3.33volts

For 2ohms resistor

V = 3.33×2

V = 6.66volts

For 3ohms resistor

V = 3.33×3

V = 9.99volts

3 0
3 years ago
Read 2 more answers
Other questions:
  • Last question bottom
    13·1 answer
  • Global Precipitation Measurement (GPM) is a tool scientists use to forecast weather. Which statements describe GPM? Select three
    7·1 answer
  • Two identical point charges of +Q coul are separated by a distance of 10 cm.
    11·1 answer
  • _____cells do not contain a nucleus
    6·1 answer
  • A man does 4,475 J of work in the process of pushing his 2.50 103 kg truck from rest to a speed of v, over a distance of 26.0 m.
    9·1 answer
  • A student pushed a 100 N bicycle over a distance of 15 m in 5 s. calculate the power generated.
    8·1 answer
  • A soccer player practices kicking the ball into the goal from halfway down the soccer field. The time it takes for the ball to g
    9·2 answers
  • Which formations are created by wave erosion?
    8·1 answer
  • If neutron stars are squeezed harder they collapse into black hole; how would this transition occur?
    15·1 answer
  • 49. \ A rectangular plate is rotating with a constant angular speed about an axis that passes perpendicularly through one corner
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!