Question

A car starts from rest and travels for 7.5 s with a uniform
acceleration of +2.8 m/s^{2}. The driver then applies the
brakes, causing a uniform acceleration of −2.5 m/s^{2}.If
the brakes are applied for 1.0 s, determine each of the
following.

(a) How fast is the car going at the end of the braking period?
m/s

(b) How far has the car gone? m

Answer #1

For distance:

d=Vt+1/2at^2

where V=starting velocity

d=(0)(7.5)+1/2(2.8)(7.5)^2

d=78.75 meter

For the velocity at the instant of applying the brakes:

v=V+at

v=0+(2.8)(7.5)

v=21 m/s

Then the driver applies the brakes for deceleration of 2.5 m/s^2
for 1 seconds

the final velocity will be

V(final)=v+AT , where A= deceleration of 2.5 m/s^2 and T= time of
braking of 1 s

V(final)=21+(-2.5)(1) ---> A is negative because it is
deceleration or acceleration at negative direction

therefore

V(final)=18.5 m/s

The distance from the instant of braking to the final position will
be:

D=vT+1/2AT^2

D=(21)(1)+1/2(-2.5)(1)^2

D=19.75 m

Therefore the total distance is

total distance=d+D

total distance=78.75+19.75

total distance=98.5 meters

A car starts from rest and travels for 8.0 s with a uniform
acceleration of +1.8 m/s2. The driver then applies the
brakes, causing a uniform acceleration of -2.0 m/s2. If
the brakes are applied for 3.0 s, determine each of the
following.
(a) How fast is the car going at the end of the braking
period?
(b) How far has it gone?

The wheels on a car have a radius of 0.250 m. The car starts
from rest and the driver accelerates the car at a constant rate and
reaches a speed of 47.0 miles per hour in 7.0 s. a) Calculate the
angular acceleration of the wheels of the car. b) The driver
applies the brakes for 5.0 s which decelerates the car at a rate of
15.0 rad/s2. Calculate the total distance the car traveled during
the entire 12.0 s...

A car starts from rest and travels east with an acceleration of
4x10^-3 m/s^2. Another car travels toward west at a constant speed
of 70kph. The two cars are 100-km apart. Find (a) the time it takes
for the two cars to meet and (b) the time it takes for them to be
100-km apart for the second time.

A
train starts from rest and begins a constant acceleration of 0.75
m/min^2. How long will it take the train to go 3.0 kilometers? How
fast is the train going when it has gone 2.0 kilometers?
A car is going 120 km/hr when it begins to deaccelerate at a
constant 15 km/min^2 until it stops. How far did the car travel
during the deacceleration?

a car starts from rest and accelerates uniformly, until it has
traveled 15km and acquired a velocity of 30m/s. the car then moves
at this constant velocity of 30 m/s for 15 minutes. the driver then
applied the brakes and the car stopped after 5 minutes.
find
the acceleration during the last part of the trip: a1=
The acceleration during the last part of the trip: a3=
The total distance traveled during the whole trip: dtot=

Suppose that a car starts from rest its engine providing an
acceleration of 10gt/s while air resistance provides 0.1 ft/s^2 of
deceleration for each foot per second of the cars velocity
Find
b) Find how long it takes the car to attain 90% of its limiting
velocity and how far it travels while doing so

A race car starts from rest and travels east along a straight
and level track. First part of the motion the car’s velocity is
given by 13 m/s after which it starts to accelerate. What is the
acceleration of the car if it reaches to a velocity of 46.12 m/s
after 19 s.

A car of mass 772 kg is traveling 26.4 m/s when the driver
applies the brakes, which lock the wheels. The car skids for 4.47 s
in the positive x-direction before coming to rest.
HINT
(a)
What is the car's acceleration (in m/s2)? (Indicate
the direction with the sign of your answer.)
m/s2
(b)
What magnitude force (in N) acted on the car during this
time?
N
(c)
How far (in m) did the car travel?
m

A Train on a straight railway track starts from rest and
accelerates at 2.0 m/s2 in 10sec. Then the train covers a distance
of 300 m at constant speed for 20 sec until the brakes are applied,
stopping the train in a uniform manner in an additional 5.0 s. (a)
How far is the train in first 30sec? (b) What is the average
velocity of the train for the complete journey?

A ball starts from rest and rolls down a hill with uniform
acceleration, traveling 160 m during the second 5.1 s of its
motion.
How far did it roll during the first 5.1 s of motion?
Express your answer to two significant figures and include the
appropriate units.

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 16 minutes ago

asked 17 minutes ago

asked 25 minutes ago

asked 25 minutes ago

asked 28 minutes ago

asked 34 minutes ago

asked 34 minutes ago

asked 45 minutes ago

asked 59 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago