Grade 10Mechanics

a man can swim at 6 km/hour. The speed of a stream is 2 km/hour. How much time will the man take to swim 400m if(a) he is swimming with the stream?(b) he is swimming against the stream?

siva

8 Years agoGrade 10

1 Answer

Arun

8 Years ago

Dear Student

(a)

if he is swimming with the stream, the resultant velocity = 6+2 = 8 km/hr

= 8 * 5/18 = 20/9 m/sec

now

time = distance /speed = 400/ (20/9)

= 180 sec = 3 minutes

(b)

if against the stream, resultant velocity = 6 – 2 = 4 km/hr

= 4 * 5/18 = 10/9 m/sec

hence time taken = 400 / (10/9)

= 360 sec = 6 minutes

Regards

Arun (askIITians forum expert)

Three identical balls are placed on a frictionless horizontal surface touching each other. They stick to each other because of adhesive. Another ball of same radius and mass m is placed over the void created by the three balls. Find the forces applied by the balls kept on the floor to each other if the system remains in equilibrium.

mechanics

1 Answer Available

Last Activity: 10 Months ago

A car loaded with water having total mass 1000 kg moves on a straight horizontal Road starting from rest under the action of a force of 100 Newton. The water spills throw a small hole in the bottom at a rate of 0.1 KG per second the velocity of cart after 300 seconds is nearly.

11
21
31
41

mechanics

1 Answer Available

Last Activity: 10 Months ago

A metal strip clamped at one end vibrates with a frequency of 20 Hz and amplitude of 5 mm
at the free end, where a small mass of 2 g is positioned. determine
(i) The velocity of the end when passing through the zero position
(ii) The acceleration at maximum displacement
(iii) The maximum kinetic energy of the mass

mechanics

2 Answers Available

Last Activity: 3 Years ago

An object of mass m = 0.25 kg oscillates in a fluid at the end of a vertical spring of spring
constant kH = 85 N/m, see Fig.1. The effect of the fluid resistance is governed by the
damping constant b = 0.07kg/s.
(i) Find the period of the damped oscillation.
(ii) By what percentage does the amplitude of the oscillation decrease in each cycle?

mechanics

1 Answer Available

Last Activity: 3 Years ago

If a=x² find the displacement at t =3sec if body velocity at t= 0 sec is 0

mechanics

1 Answer Available

Last Activity: 3 Years ago

View all Questions

a man can swim at 6 km/hour. The speed of a stream is 2 km/hour. How much time will the man take to swim 400m if(a) he is swimming with the stream?(b) he is swimming against the stream?

siva

1 Answer

Arun

Other Related Questions on mechanics

A car loaded with water having total mass 1000 kg moves on a straight horizontal Road starting from rest under the action of a force of 100 Newton. The water spills throw a small hole in the bottom at a rate of 0.1 KG per second the velocity of cart after 300 seconds is nearly.11213141

If a=x² find the displacement at t =3sec if body velocity at t= 0 sec is 0

A car loaded with water having total mass 1000 kg moves on a straight horizontal Road starting from rest under the action of a force of 100 Newton. The water spills throw a small hole in the bottom at a rate of 0.1 KG per second the velocity of cart after 300 seconds is nearly.

11
21
31
41