Question

. (i) A child is sledding down an ice covered hill. Each of the two runners on the sled
has dimensions of 1.1 m by 1.3 cm. The sled is supported on a thin film of water h
= 0.15 mm, µ= 0.001 kg/(m-s)] created by a local melting of the ice due to the
pressure exerted by the sled. If the child is cruising at a velocity of 8 m/s,
calculate: a) the total shear stress on the runners of the sled b) the shear strain
rate for this flow c) the magnitude of the force on one of the runners of the sled.
10
(ii) Calculate the capillary rise in a glass tube of 3 mm diameter when immersed
vertically in (a) water, (b) mercury. Take surface tension for mercury and water as
0.515 N/m and 0.0735 N/m respectively in contact with air.

Answer 1

Answer:

Given : Velocity of sound in air v=344 ms

−1

Wavelength of the sound waves λ=

ν

v

For ν

1

=20 Hz, λ

1

=

20

344

=17.2 m

For ν

2

=20 kHz, λ

2

=

20×1000

344

=1.72×10

−2

m

Explanation:

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