INTERNAL
Semester Two, 2016
Unit Code and Title ENS2113
ENGINEERING D YNAMICS STANDARD PAPER
Surname Given Name(s) Student Number
Duration
Expected Time to Complete 2 hours
Attempt
All 5 examples
Marks
All examples carry equal marks (10 points per example)
Type of Exam
Take Home Exam
Exam is to be completed at home and returned by the given
date.
Special Instructions
• This is not an assignment. There is no facility for late submission.
• This examination paper consists of 1 part.
• All questions should be attempted using one of the following models of calculators only: Casio FX-100, Sharp EL520WGBK.
• There are a total of 12 pages.
• Some exam papers are double sided – please check both sides of the page
• Please record all your answers in the provided
Answer Booklet
Problem 1:
A camera is tracking the ECU Formula Student car as it accelerates in a straight line at a constant rate of 11ms-2. Calculate 𝑟, 𝑟?, 𝑟¨ and 𝜃, 𝜃?, 𝜃¨ for both the instant shown and in 1s from the instant shown (assume acceleration remains constant).

Problem 2:
The ECU Formula Student car is being driven up a gradient of 5°. Its velocity starts at 10ms-1. The vehicle and driver have a combined mass of 250kg. There is a rolling resistance (friction) of µ=0.05. There is a constant accelerating force (Thrust) of 2000N and an opposing drag force of 250(1+t)N. Calculate the following:
- Speed of the vehicle after 1.5 seconds
- Impulse due to the drag force over 1.5 seconds
- The change in potential and kinetic energy after 1.5s

Problem 3:
The ECU Formula Student car is equipped with a water pump that flows 130L/min (density of water = 1000kg/m3). The water is turned through 90° at the pump, with an inlet diameter of 20mm, and an outlet diameter of 16mm. Calculate the x and y
components of the force applied on the pump by the flow of water. What other forces might you need to consider when designing a mount for the pump?
Problem 4:
The ECU Formula Student car uses a suspension system that can be approximated by a 4 bar linkage as shown in the given side view. Note that the upper link is at 10º to the horizontal and the lower link is horizontal. For the position shown point A moves to a point 25mm higher in 0.5s at a constant radial velocity.
Calculate the following:
a) The initial position of the instantaneous centre of the upright
b) The radial velocity of the lower link
c) The radial velocity of the upright
d) The angle of the upright to the horizontal after point A has moved upwards 25mm


Problem 5:
When the driver turns the front wheels of the ECU Formula Student car they produce a lateral (sideways, x) force of 1500N. The vehicle and driver’s combined weight is 250kg and they have a radius of gyration of 0.6m. The front wheels are situated 0.8m forward of the centre of gravity, and the rear wheels are situated 0.7m to the rear of the centre of gravity.
Calculate the following:
- Lateral and rotational acceleration due to this force
- The force required at the rear wheels in order for there to be no rotational acceleration, and the corresponding lateral acceleration


-END OF EXAM PAPER-