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
DENIUS [597]
3 years ago
15

The driver of a car slams on the brakes when he sees a tree blocking the road. the car slows uniformly with acceleration of -5.9

0 m/s2 for 4.15 s, making straight skid marks 62.3 m long, all the way to the tree. with what speed does the car then strike the tree?
Physics
1 answer:
Hatshy [7]3 years ago
4 0
Let u =  the speed of the car at the instant when braking begins.

The braking distance is s = 62.3 m, the acceleration is a = -5.9 m/s², and the braking duration is t = 4.15 s.

Use the formula s = ut + (1/2)at² to obtain
(u m/s)*(4.15 s) + 0.5*(-5.9 m/s²)*(4.5 s)² = (62.3 m)
4.15u = 62.3 + 50.8064 = 113.1064
      u = 27.2546 m/s

Let v m/s be the speed with which the car strikes the tree.
Then
v = 27.2546 - 5.9*4.15
   = 2.7696 m/s

Answer: 2.77 m/s (nearest hundredth)

You might be interested in
How much current will pass through a 12.5 ohm resistor when it is connected to ta 115 volt source of electrical potential?
Marrrta [24]

Answer:

9.2 amperes

Explanation:

Ohm's law states that the voltage V across a conductor of resistance R is given by V = R I

Here, voltage V is proportional to the current I.

For voltage, unit is volts (V)

For current, unit is amperes (A)

For resistance, unit is Ohms (Ω)

Put R = 12.5 and V = 115 in V=RI

115=12.5I\\I=\frac{115}{12.5}\\ =9.2\,\,amperes

8 0
3 years ago
The tops of the towers of the Golden Gate Bridge in San franciscoo , are 227 m above the water. Suppose a worker drops a 655 g w
yaroslaw [1]

Answer:

Kinetic energy is 1425.11 J.

Explanation:

Given:

Mass of the wrench is, m=655\ g=0.655\ kg

Height of fall is, h=227\ m

Force of resistance is, F=0.141\ N

Now, the total energy at the top is equal to the potential energy of the wrench at the top since the kinetic energy at the top is 0.

Now, potential energy at the top is given as:

U=mgh\\U=0.655\times 9.8\times 227\\U=1457.113\ J

Now, the potential energy at the top is converted to kinetic energy at the bottom and some energy is wasted in overcoming the resistance force by air.

Potential Energy = Kinetic energy + Energy to overcome resistance.

⇒ Kinetic energy = Potential Energy - Energy to overcome resistance.

Energy to overcome resistance force is the work done by the wrench against the resistance force and is given as:

W_{res}=Fh=0.141\times 227=32.007\ J

Therefore, Kinetic energy at the bottom is given as:

K=U-W_{res}\\\\K=1457.113\ J - 32.007\ J\\\\K=1425.106\approx1425.11\ J

Hence, the kinetic energy of the wrench be when it hits the water is 1425.11 J.

7 0
3 years ago
Vector ????⃗ has a magnitude of 16.6 and is at an angle of 50.5∘ counterclockwise from the +x‑axis. Vector ????⃗ has a magnitude
natka813 [3]

Answer:

For vector u, x component = 10.558 and  y component =12.808

unit vector = 0.636 i+ 0.7716 j

For vector v, x component = 23.6316 and y component = -6.464

unit vector = 0.9645 i-0.2638 j

Explanation:

Let the vector u has magnitude 16.6

u makes an angle of 50.5° from x axis

So u_x=ucos\Theta =16.6\times cos50.5=10.558

Vertical component u_y=usin\Theta =16.6\times sin50.5=12.808

So vector u will be u = 10.558 i+12.808 j

Unit vector u=\frac{10.558i+12.808j}{\sqrt{10.558^2+12.808^2}}=0.636i+0.7716j

Now in second case let vector v has a magnitude of 24.5

Making an angle with -15.3° from x axis

So horizontal component v_x=vcos\Theta =24.5\times cos(-15.3)=23.6316

Vertical component v_y=vsin\Theta =24.5\times sin(-15.3)=-6.464

So vector v will be 23.6316 i - 6.464 j

Unit vector of v =\frac{23.6316i-6.464}{\sqrt{23.6316^2+6.464^2}}=0.9645i-0.2638j

8 0
3 years ago
Two point charges of equal magnitude q are held a distance d apart. Consider only points on the line passing through both charge
NemiM [27]

let us consider that the two charges are of opposite nature .hence they will constitute a dipole .the separation distance is given as d and magnitude of each charges is q.

the mathematical formula for potential is V=\frac{1}{4\pi\epsilon} \frac{q}{d}

for positive charges the potential is positive and is negative for negative charges.

the formula for electric field is given as-E=\frac{1}{4\pi\epsilon} \frac{q}{r^2}

for positive charges,the line filed is away from it and for negative charges the filed is towards it.

we know that on equitorial line the potential is zero.hence all the points situated on the line passing through centre of the dipole and perpendicular to the dipole length is zero.

here the net electric field due to the dipole can not be zero  between the two charges,but we can find the points situated on the axial  line but  outside of charges where the electric field is zero.

now let the two charges of same nature.let these are positively charged.

here we can not find a point between two charges and on the line joining  two charges  where the potential is zero.

but at the mid point of the line joining two charges the filed is zero.

5 0
3 years ago
If you can swim in still water at 0.5m/s, the shortest time it would take you to swim from bank to bank across a 20m wide river,
expeople1 [14]

Answer:

t=40s,

Explanation:

If you can swim in still water at 0.5m/s, the shortest time it would take you to swim from bank to bank across a 20m wide river, if the water flows downstream at a rate of 1.5m/s, is most nearly:

from the question the swimmer will have a velocity which is equal to the sum of the speed of the water and the velocity to swi across the bank

Vt=v1+v2

the time is takes to swim across the bank will be

DY=Dv*t

DY=distance across the bank

Dv=ther velocity of the swimmer across the bank

t=20/ 0.5m/s,

t=40s, time it takes to swim across the bank

velocity is the rate of displacement

displacement is distance covered in a specific direction

4 0
3 years ago
Read 2 more answers
Other questions:
  • Water waves in a small tank are .06 m long. They pass a given point at a rate of 14.8 waves every three seconds. What is the spe
    8·1 answer
  • Two elements in Period 4 that are most similar to Cobalt?
    8·1 answer
  • An ideal gas is enclosed in a piston, and 1600 J of work is done on the gas. As this happens, the internal energy of the gas inc
    8·1 answer
  • Identical marbles are released from the same height on each of the following four frictionless ramps . Compare the speed of the
    8·1 answer
  • Aliens come blasting into our solar system and wipe out everything but the Sun, the Earth, and Jupiter. Discuss (conceptually) w
    10·1 answer
  • The formula for sodium sulfide is na2s what does it mean
    8·1 answer
  • How many significant figures are in 73,102L
    7·1 answer
  • The speed of a moving bullet can be deter-
    15·1 answer
  • Science question: How do humans use the magnetic field for navigation?
    7·1 answer
  • PLEASE HELP
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!