Question

A wire is suspended from the ceiling and stretched under the action of a weight F suspended from its other end. The force exerted by the ceiling on it is equal and opposite to the weight. *
tensile stress at any cross section A of the wire is F/A
tensile stress at any cross section is zero
tensile stress at any cross section A of the wire is 2F/A.
tensile stress at any cross section A of the wire is F
A copper and a steel wire of the same diameter are connected end to end. A deforming force F is applied to this composite wire which causes a total elongation of 2cm. The two wires will have *
the same stress
different stress
the same strain
none of the above
If a load of 1 kg stretched a cord by 1.2cm, what is the force constant of the cord? [g= 10m/s] *
866 Nm-1
833 Nm-1
769 Nm-1
667 Nm-1
The total length of a spring when a mass if 20g is hung from its end is 14cm, while its total length is 16cm when a mass of 30g is hung from the same end. Calculate the unstretched length of the spring assuming Hooke’s law is obeyed *
9.33cm
10.0cm
10.66cm
12.00cm
A 10g mass placed in the pan of a spring balance causes an extension of 5cm. if a 15g mass is placed on the same spring balance, the extension is *
3.3cm
6.5cm
7.5cm
10.8cm
A force of 50N stretches a wire from 20m to 20.01m, what is the amount of force required to stretch the same material from 20m to 20.05m *
205N
400N
250N
300N
A 10g mass placed on the pan of a spring balance causes an extension of 5cm. If a 15g mass s placed on the pan of the same spring balance, what will be the new extension? *
7.5cm
5.5cm
3.0cm
9.0cm
If the load of mass 10N stretched a cord by 1.2cm, what is the total work? *
6.0 X 10-2J
7.6 X 10-2J
1.8 X 10-2J
6.6 X 10-2J
Calculate the work done when a force of 20N stretches a spring by 50mm. *
0.5J
1.5J
2.0J
2.5J
If a load of mass 10N stretches a cord by 1.2cm, what is the total work-done? *
60000000J
0.06J
90000000 J
1900000 J
Load of 20N on a wire of cross-sectional area 8 X10-7 m2, producing an extension of 10-5 m. Calculate Young’s modulus for the material of the wire if its length is 3m *
7.0 X 10^11 Nm-2
7.5 X 10^12 Nm-2
8.5 X 10^11 Nm-2
9.0 X 10^11 Nm-2
A catapult used to hold a stone of mass 500g is extended by 20cm with an applied force F. if the stone leaves with a velocity of 40m/s, what is the value of F *
4.0 X 10^2 N
2.0 X 10^3 N
4.0 X 10^3 N
4.0 X 10^4 N
On top of a spring of the force constant 500 Nm-1 is placed a mass of 5 X 10-3 kg.if the spring is compressed downwards by a length of 0.02m and then released, calculate the height to which the mass is projected *
8m
4m
2m
1m

Answer 1

Answer:

When a wire is suspended from the ceiling and stretched under the action of a weight (F) suspended from its other end, the force exeted by the ceiling on it is equal and opposite to the weight. However, the tension at any cross section A of the wire is just F and not 2F.