Mechanical Engineering Answers

Two parallel shafts are to be connected by spur gearing. The approximate distance between the shafts is 600 mm. If one shaft runs at 120 r.p.m. and the other at 360 r.p.m., find the number of teeth on each wheel if the module is 8 mm. Also determine the exact distance apart of the shafts.

A compound train consists of six gears. The number of teeth on the gears are as follows:

Gear : AB C DE F

No. of teeth : 60 40 50 25 30 24

The gears B and C are on one shaft while the gears D and E are on another shaft. The gear A drives gear B, gear C drives gear D and gear E drives gear F. If the gear A transmits 1.5 kW at 100 r.p.m. and the gear

train has an efficiency of 80 per cent, find the torque on gear F.

1. An engine working on otto cycle has a volume of 0.5 m^3  pressure 1 bar and temperature 27C at the commencement of compression stroke.At the end of compression stoke,the pressure is 10 bar. Heat added during the constant volume process is 200 kJ.Determine
2. Percentage clearance
3. Air standard efficiency
4. Mean effectine pressure
5. Ideal power developed by the engine if the engine runs at 400 r.p.m.so that there are 200 cycles per minute.

The efficiency of an otto cycle is 50% and Y= 1.5 .What is the compression Ratio?

1. A diesel engine has a compression ratio of 18 and cut- off takes place at 5% the stroke . calculate the air standard efficiency. Y=1.4

Two 5m x 5m thin-walled parallel plates are separated by a distance of 1 mm. Air (properties shown below at the external fluid) flows over the TOP AND BOTTOM of the parallel plate stack. You may assume fully developed hydrodynamic and thermal boundary layers between the parallel plates. Using the drawing and information below, what is the outlet mean temperature of the internal fluid?

Give a complete design analysis of a single plate clutch, with both sides effective, of a vehicle to transmit 22 kW at a speed of 2800 r.p.m. allowing for 25% overload. The pressure intensity is not to exceed 0.08 N/mm2 and the surface speed at the mean radius is not to exceed 2000 m/min. Take coefficient of friction for the surfaces as 0.35 and the outside diameter of the surfaces is to be 1.5 times the inside diameter. The axial thrust is to be provided by 6 springs of about 24 mm coil diameter. For spring material, the safe shear stress is to be limited to 420 MPa and the modulus of rigidity may be taken as 80 kN/mm2

In a crank and slotted lever mechanism, the driving crank is 35 mm long, and the time ratio of cutting stroke to return stroke is 1.6. If the length of working stroke of the ram is 110 mm, find the distance between the fixed centers, and the slotted lever length.

It is important that the karts can brake effectively. They use drum brakes where a solid circular drum of mass 4.0 kg and radius 0.15 m is rotating at an angular speed of 22 rad s−1 about an axis when a ‘braking’ torque is applied to it which brings it to rest in 5.8 s.

Calculate

i) its angular deceleration when the braking torque is applied.

ii) the moment of inertia of the drum about the axis shown

𝐼 = 1 𝑚𝑟2 2

iii) the resultant torque that causes it to decelerate.

Your go karts have a mass of 450kg and travel around a circular curve on a flat, horizontal track at a radius of 42 m.

a) Draw a diagram to show the go kart on the track and add an arrow to show the direction of the frictional force needed for the car to travel around the curve at a radius of 42 m.

b) The maximum frictional force between the tyres and the road is equal to 20% of the weight of the car and driver. Calculate the coefficient of friction when an adult of mass 70kg is driving the kart.

c) Calculate maximum angular velocity at which the car can travel round the curve at a constant radius of 42 m.

d) Calculate the maximum linear velocity.

e) You decide that this is not nearly fast enough and decide to create a banked track of 12O, what is the maximum linear velocity now?

f) Describe qualitatively how this could change if a child were driving the kart.