Question

1. 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.
2. Calculate the mass of the vehicle in kg, if the grade resistance is 82 N, the road grade is 1.1.
3. Find the rolling resistance (in N) when: the rolling coef. is 0.014, the effective mass is 81 kg.
4. 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.