Question

- Calculate the change in kinetic energy in J, when the mass is 56 kg, the initial velocity is 45 m/s and the final velocity is 90 m/s.
- Calculate the mass of the vehicle in kg, if the grade resistance is 82 N, the road grade is 1.1.
- Find the rolling resistance (in N) when: the rolling coef. is 0.014, the effective mass is 81 kg.
- Find F(aero) (in N) if the total tractive effort is 73 kN, the rolling resistance is 103 N, the grade resistance is 7.3 kN, and the inertia force is 92 N.

Answer #1

1] Change in kinetic energy is:

=>

2]

Grade resistance is the component of gravitational force acting downwards along the slope.

road grade = slope of the inclined =

therefore,

=> m = 11.308 kg

this is the mass of the vehicle.

3] Rolling resistance is given by:

F = mg(d/r)

where r = radius and d = horizontal distance from center to the point of contact for the two forces. d/r is the rolling coefficient and here d/r = 0.014

therefore, Rolling resistance = mg(0.014) = 11.1132 N.

Find the kinetic energy of the objects in the scenarios.
A. A cosmic pion of mass 140 MeV/c2140 MeV/c2 flies through
outer space at a speed of 9.47×103 km/s9.47×103 km/s. See the hint
for help converting MeV/c2MeV/c2 to kg.
K=K=
JJ
B. A cheetah weighing 6.20×102 N6.20×102 N chases a gazelle at a
speed of 30.1 m/s30.1 m/s.
K=K=
JJ
C. A truck weighing 2.24 short tons2.24 short tons speeds down
the road at 66.6 mph66.6 mph.
K=K=
JJ
D....

7. Ball A with mass 0.85 kg is rolling at 3.5
m/s [N] when it collides with stationary Ball B with mass 1.15 kg.
After the collision, Ball A is moving 2.4 m/s [N40ºW]. Find the
velocity of Ball B after the collision.

Find the kinetic energy of the objects in the scenarios.
A. A cosmic pion of mass 140 MeV/c2 flies through outer space at
a speed of 9.61×103 km/s. See the hint for help converting MeV/c2
to kg.
K=_____ J
B. A cheetah weighing 6.20×102 N chases a gazelle at a speed of
33.1 m/s.
K=______J
C. A truck weighing 3.24 short tons speeds down the road at 65.1
mph.
K=______J
D. An asteroid of mass 2.43×1017 kg buzzes the Earth...

An
object of mass 1700 kg is moving at an initial velocity 11.3 x̂ x^
m/s . A force of -20.2 ŷ y^ kN is exerted on it for a time of 0.30
seconds. Calculate the final speed of the object in m/s to 3
sf.

A professional driver is taking a race car of mass 1,270 kg out
for a test drive on a circular track of radius 140 m. Starting from
rest, the driver applies the throttle so that there is a constant
force of 2,500 N on the car in the direction of its motion. What is
the angular velocity of the car after 30 seconds? Assume that the
car’s wheels maintain traction on the road.
Select one: a. 0.014 rad / s...

8. (a) Calculate the potential energy of a 10.0-kg mass on the
surface of the Earth and at an altitude of 400 km respectively; (b)
calculate the speed needed to move this mass from surface of the
Earth to the altitude of 400
km. (-6.25*108 J, -5.88*108
J, 2.72*103 m/s)

A soccer ball of mass 0.30 kg is rolling with velocity 0, 0, 3.0
m/s, when you kick it. Your kick delivers an impulse of magnitude
1.6 N · s in the −x direction. The net force on the rolling ball,
due to the air and the grass, is 0.28 N in the direction opposite
to the direction of the ball's momentum. Using a time step of 0.5
s, find the position of the ball at a time 1.5 s...

A soccer ball of mass 0.31 kg is rolling with velocity <0, 0,
2.1> m/s, when you kick it. Your kick delivers an impulse of
magnitude 2.7 N·s in the -x direction. The net force on the rolling
ball, due to the air and the grass, is 0.37 N in the direction
opposite to the direction of the ball's momentum. Using a time step
of 0.5 s, find the position of the ball at a time 1.5 s after you...

7. A 500 kg car goes around turn in the road that has a radius
of curvature of 5 m. The car is traveling at a constant speed of 10
m/s.
(i) What is the centripetal force required to keep the car from
sliding out as it goes around the turn?
(ii) What must be the coefficient of friction between the tires
of the car and the road in order for the car to not sliding as it
goes around...

12) There are several types of drag on a car other than air
resistance. Effects having to do with the squeezing of the tires
(rolling resistance) and frictional forces in the drivetrain (the
system that transfers energy from the engine to the rotation of the
wheels) also must be taken into account. Engineers use the
following equation to model the total force due to these different
effects
Fdrag=A+Bv+Cv2Fdrag=A+Bv+Cv2
For a Camry, these coefficients are estimated to be
A=117.130A=117.130 N, B=1.800...

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