Example
:
1. The
vulcanic material of mass 10 tons is thrown
vertical upward. The height of it that can be reached is 15,000 meters.
The work of vulcano is ….( g = 10 N/kg)
Solution
:
W=
m.g.h
=10000 kg.10 N/kg.15000 m
= 1,500,000,000 J
2.
A box contains substance of metal totalize1,000 Newton in boosting up to use
inclined plane similar at the picture. Force of power minimum which is needing
in order to can make move going up is ….
3 m
4 m
Solution
:
s2 = 32+42
; s = 5m
F= w .h /s = 1000N . 3m / 5m = 600 N
2. A lever with burden arm 50 cm, lever length 2 m, burden weight 600
Newton, hence the minimum power force (F) used the burden to earn
upraised is….
Solution :
F= w.lw / lf = 600 N. 50cm / 150 cm = 200 N
3. Consider the
picture burden as heavy as 230 Newton, lifted by using free pulley, weight the
pulley 10 Newton, hence the power force (F) that is needed minimize
upraised in order to….
Solution
:
F = ½.W
= ½. (230+10)N = 120 N.
4. The bread of width 12 cm will be cut with a knife.
The force applied is 24 N and the sharp edge has a thickness of 0.4 mm.
The pressure exerted on the bread is ….
Solution
:
A = 12 cm x 0.4 mm
= 120 mm x 0.4 mm
= 48 mm2
= 48 /10000 m2
P = F / A = 24 N / 48 m2
= 5000 N
10000
5. Given F1 = 12000N, A1=60 A2. The magnitude of
force required to lift the car is ….
Solution
:
F2 =
(F1.A2) / A1 = 12000N . A2 / 60 A2
= 200 N
6.
How much minimally force will be needed to pull the
object of mass 15.5 kg, out of the water, if the volume of the object 0.0005 m3?
(the weight of pulley is ignored, ρ water = 1000 kg/m3, g
= 10N/kg).
Solution :
FA =
ρ.g.V = 1000 kg .10 N/kg . 0.0005 m3
= 5 N
F =1/2( m.g - FA )=1/2 (15.5 kg . 10N/kg) - 5 N) =1/2( 155 N – 5 N) =1/2x 150 N=75N
7.
A body is pushed with force of 36 N, so
that it moves in acceleration. If the
mass of a body is 6 kg and there is no friction which works on the body,
then the acceleration of the body is….
Solution
:
a
= F/m = 36 N/ 6kg = 6 ms-2
8. Mass of the body is 30 kg on the Earth. Given
earth gravitational acceleration is 10 m/s2. If on the moon
acceleration due to gravity is 1/6 of acceleration due to gravity on the earth,
then the body’s weight on the moon is ....
Solution
:
Wm
= 1/6 . m.g = 1/6 x 30 kg x 10 ms2 = 50 N
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