Advertisements
Advertisements
Question
Explain why, when a fireman directs a powerful stream of water on a fire from a hose pipe, the hose pipe tends to go backward.
Solution
When a fireman directs a powerful stream of water on fire from a hose pipe, he has to hold the hose pipe strongly because of its tendency to go backwards. The backward movement of the hose pipe is due to the backward reaction of the water rushing through it in the forward direction at a great speed.
APPEARS IN
RELATED QUESTIONS
A stone of 1 kg is thrown with a velocity of 20 m s−1 across the frozen surface of a lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice?
Using a horizontal force of 200 N, we intend to move a wooden cabinet across a floor at a constant velocity. What is the friction force that will be exerted on the cabinet?
Is the following statement true or false :
A rocket can propel itself in a vacuum.
A girl weighing 25 kg stands on the tloor. She exerts a downward force of 250 N on the floor. What force does the floor exert on her ?
If action is always equal to reaction, explain why a cart pulled by a horse can be moved.
Do action and reaction act on the same body or different bodies ? How are they related in magnitude and direction ? Are they simultaneous or not ?
Why is it difficult to walk on a slippery road ?
Draw a diagram to show how a rocket engine provides a force to move the rocket upwards. Label the diagram appropriately.
Give a scientific reason.
Even though the magnitudes of action force and reaction forces are equal and their directions are opposite, their effects do not get cancelled.
Consider a frame that is made up of two thin massless rods AB and AC as shown in the figure. A vertical force `vec"P"` of magnitude 100 N is applied at point A of the frame.
Suppose the force is `vec"P"` resolved parallel to the arms AB and AC of the frame.
The magnitude of the resolved component along the arm AC is xN.
The value of x, to the nearest integer, is ______.
[Given: sin(35°) = 0.573, cos(35°) = 0.819, sin(110°) = 0.939, cos(110°) = –0.342]
