Statics of a Particle 24Oct09

1

• Statics of a Particle 24-Oct-09
• Find a resultant force
• Split a force into desired components

2
8 N
Use the cosine rule for r and sine rule for F
r
8
1000
800
800
F
6
6 N
r v(82 62 2x 6 x 8 x cos1000)
r 10.8 Newtons sinF/8 sin100/10.8 sinF 8 x
sin100/8 ? F 46.90
What single force (THE RESULTANT) is equivalent
to these two forces?
3
v(7.42 7.92) 10.8 tanF 7.9/7.4 F 46.90
8 N
8
1000
800
800
6
6 N
6i 0j 8cos80i 8 sin80j (6 1.4)i (0
7.9)j 7.4i 7.9j
What single force (THE RESULTANT) is equivalent
to these two forces?
4
A particle P is acted upon by three forces a, b
and c as shown. What single force d is required
to keep P in equilibrium?
3N
5N
b
a
1000
300
1100
p

• Put the vectors in the addition form
• a b c r

c
b
c
2N

• Change the forces into i j form
• a 5cos30 5sin30 ? 4.3i 2.5j
• b 3cos130 3sin130 ? -1.9i 2.3j
• c 2cos240 2sin240 ? -1i 1.7j
• ? (4.3 -1.9 1)i (2.5 2.3 1.7)i r
• 1.4i 3.1j r

r
a
5
A particle P is acted upon by three forces a, b
and c as shown. What single force d is required
to keep P in equilibrium?
3N
5N
b
a
1000
300
1100
p
Put the vectors in the addition form ? a b c
d 0
c
b
c
2N
Change the forces into i j form a 5cos30
5sin30 ? 4.3i 2.5j b 3cos130 3sin130 ?
-1.9i 2.3j c 2cos240 2sin240 ? -1i 1.7j ?
((4.3 -1.9 1) x)i ((2.5 2.3 1.7)
y)i 0i 0j ? 1.4 x 0 and 3.1 y 0 ? x
-1.4 and y -3.1
d
a
d xi yj