NCERT Solution
Class 9
Science
Force and Laws of Motion
a bullet of mass 10 g travelling horizontally with...

Question:
A bullet of mass 10 g travelling horizontally with a velocity of 150 m s^-1 strikes a stationary wooden block and comes to rest in 0.03 s. Calculate the distance of penetration of the bullet into the block. Also calculate the magnitude of the force exerted by the wooden block on the bullet.

Answer:

Mass of bullet, m = 10 g = 10 / 1000 = 0.01 kg

Initial velocity, u = 150 m/s

Final velocity, v = 0

Time taken, t = 0.03 s

Using the first equation of motion

v = u + at

0 = 150 + (a ×0.03 s)

(Negative sign indicates that the velocity of the bullet is decreasing.)

Now, using the third equation of motion:

v₂ = u₂ + 2as

0 = (150)2 + 2 (−5000) s

Hence, the distance of penetration of the bullet is 2.25 m.

We know that

Force, F = Mass × Acceleration

F = ma = 0.01 × 5000 = 50 N

Hence, the magnitude of force is 50 N.

1
0
0
Report?

Report a problem on Specifications:

Email id:

Comments

Next Question >

SELECT ex_no,question,question_no,id,chapter FROM question_mgmt as q WHERE courseId='8' AND subId='16' AND ex_no!=0 AND status=1 and id!=4146 ORDER BY views desc, last_viewed_on desc limit 0,10

Popular questions of class 9 Science

Abdul, while driving to school, computes the average speed for his trip to be 20 km h^-1. On his return trip along the same route, there is less traffic and the average speed is 40 km h^-1. What is the average speed for Abdul’s trip?

An object of mass 40 kg is raised to a height of 5 m above the ground. What is its potential energy? If the object is allowed to fall, find its kinetic energy when it is half-way down.

A driver of a car travelling at 52 km h^-1 applies the brakes and accelerates uniformly in the opposite direction. The car stops in 5 s. Another driver going at 3 km h^-1 in another car applies his brakes slowly and stops in 10 s. On the same graph paper, plot the speed versus time graphs for the two cars. Which of the two cars travelled farther after the brakes were applied?

Fig 8.11 shows the distance-time graph of three objects A,B and C. Study the graph and answer the following questions:

Fig. 8.11

(a) Which of the three is travelling the fastest?
(b) Are all three ever at the same point on the road?
(c) How far has C travelled when B passes A?
(d) How far has B travelled by the time it passes C?

Two objects, each of mass 1.5 kg, are moving in the same straight line but in opposite directions. The velocity of each object is 2.5 m s^-1 before the collision during which they stick together. What will be the velocity of the combined object after collision?

Soni says that the acceleration in an object could be zero even when several forces are acting on it. Do you agree with her? Why?

Two objects of masses 100 g and 200 g are moving along the same line and direction with velocities of 2 m s^-1 and 1 m s^-1, respectively. They collide and after the collision, the first object moves at a velocity of 1.67 m s^-1. Determine the velocity of the second object.

How do poriferan animals differ from coelenterate animals?

The speed-time graph for a car is shown is Fig. 8.12.

Fig. 8.12

(a) Find how far does the car travel in the first 4 seconds. Shade the area on the graph that represents the distance travelled by the car during the period.
(b) Which part of the graph represents uniform motion of the car?

How are sol, solution and suspension different from each other?

SELECT ex_no,question,question_no,id,chapter FROM question_mgmt as q WHERE courseId='8' AND subId='16' AND ex_no!=0 AND status=1 and id!=4146 ORDER BY last_viewed_on desc limit 0,10

Recently Viewed Questions of Class 9 Science

An object has moved through a distance. Can it have zero displacement? If yes, support your answer with an example.

What are the desirable agronomic characteristics for crop improvements?

Diagrammatically show the difference between the three types of muscle fibres.

Are the answers to the above questions necessarily the same or different? Why?

Differentiate between homogeneous and heterogeneous mixtures with examples.

Fig 8.11 shows the distance-time graph of three objects A,B and C. Study the graph and answer the following questions:

Fig. 8.11

Identify the type of tissue in the following: skin, bark of tree, bone, lining of kidney tubule, vascular bundle.

A hammer of mass 500 g, moving at 50 m s^-1, strikes a nail. The nail stops the hammer in a very short time of 0.01 s. What is the force of the nail on the hammer?

Write the electronic configuration of any one pair of isotopes and isobars.

If the organisation of a cell is destroyed due to some physical or chemical influence, what will happen?

< Previous Question

Next Question >

Popular questions of class 9 Science

Recently Viewed Questions of Class 9 Science

Comments

Comment(s) on this Question

NCERT Solutions

Quick Links

Resources

Support