Question

A rectangular wooden block has mass of 4kg. The length, breadth and height of this wooden block are 50cm, 25cm and 10cm respectively. Find the pressure on the table top: a. 50 X 25 cm side face the surface b. 25 X 10cm side face the surface of the table.

Answer 1

Answer:

Here Mass of wooden block m= 4kg

Acceleration dur to gravity ,g=10m/s2

Weight of wooden block W=m×g

=4×10

=40 N

since weight is a force,so we can say that the force excerted by the wooden block on the table top is 40 N .We will now calculate the pressure in the two cases.

(a) In the first case : Force = 40 N (Calculated above)

Area=50cm×25cm

=50100m×25100

=0.5m×0.25m

=0.125m2

Now Pressure =ForceArea

=400.125

=320Nm2 (or 320)

Thus the pressure exerted by the wooden block on table top when kept on its face measuring 50cm×25cm is 320 Nm−2 of 320 pascals (see Figure 44)

(b) In the second case : Force = 40 N (Same as above)

Area =25cm×10cm

=25100m×10100m

=0.25m×0.1m

=0.025m2

Pressre=ForceArea

=400.025

=1600Nm−2 (or 1600)

Thus the pressure exerted by the wooden block on table top when kept on its face measuring 25cm×10cm is 1600 N m−2 of 1600 pascals (see figure 45)

Answer 2

A.

mass of wooden block, m = 4kg

acceleration due to gravity,g = 10 m/s²

weight of wooden block = m × g

= 4 × 10

= 40 N

force = 40 N

Area = 0.5 m × 0.25m ( changing cm into m )

= 0.125 m

pressure = force / area

= 40 / 0.125

= 320 N m-²

B.

Force = 40N

Area = 0.25 × 0.1m

= 0.025 m²

pressure = force / area

= 40 / 0.025

= 1600 N m-² (Or 1600 pa)