Mechanical Engineering Principles

SIMPLY SUPPORTED BEAMS 67

5. Figure 5.30 [RA= 0 ,RB=0]

(e)

10 kN m 10 kN m

1 m 3 m 4 m

RA RB

Figure 5.30

6. Figure 5.31

[RA=7kN, RB=1kN]

(f)

10 kN m

RA 2 m 2 m 2 m RB

8 kN

Figure 5.31

7. Figure 5.32

[RA=−333 N, RB=333 N]

(g)

10 kN m 12 kN m

2 m

2 m

2 m 2 m

1 m

RA RB

Figure 5.32

Exercise 29 Short answer questions on
simply supported beams

1. The moment of a force is the product of
   ...and....
   2. When a beam has no tendency to move it
   is in....
   3. State the two conditions for equilibrium
   of a beam.
   4. State the principle of moments.
   5. What is meant by a simply supported
   beam?
   6. State two practical applications of simply
   supported beams.
   7. Why does a couple not have a vertical
   component of force?

Exercise 30 Multi-choice questions on

simply supported beams

(Answers on page 284)

1. A force of 10 N is applied at right angles
   to the handle of a spanner, 0.5 m from
   the centre of a nut. The moment on the
   nut is:

(a) 5 N m (b) 2 N/m

(c) 0.5 m/N (d) 15 N m

2. The distancedin Figure 5.33 when the
   beam is in equilibrium is:

(a) 0.5 m (b) 1.0 m

(c)4.0m (d)15m

20 N

2.0 m d

10 N

Figure 5.33

3. With reference to Figure 5.34, the clock-
   wise moment aboutAis:

(a) 70 N m (b) 10 N m

(c) 60 N m (d) 5×RBNm