14. A particle travels the first half of its total distance along a straight line with a speed 'V' kmph and next half with a speed of 60 kmph . If the average speed for the journey is 40 kmph the value of ' \( V \) ' is \( \qquad \) .
1) 50 kmph
2) 30 kmph
3) 120 kmph
4) 135 kmph
15. \( A B C D \) is a straight line such that \( A B=B C=C D \). A car travelled with a speed of 40 kmph from ' \( A \) ' to ' \( B \) ' and with a speed of 60 kmph from ' \( B \) ' to ' \( D \) '. Its average speed (in kmph ) in the journey from ' \( A \) ' to ' \( C \) ' and ' \( A \) ' to ' \( D \) ' are \( \qquad \) .
1) \( 48,54 \mathrm{kmph} \)
2) 51.448 kmph
3) 4851.4 kmph
4) \( 54,48 \mathrm{kmph} \)
JEE MAIN
LEVEL - 4
Single Answer Choice Type:
16. A train runs past a telegraph pole in 15 s and through a tunnel of length 450 m in 45 s . The length of the train is \( \qquad \) .
1) 225 m
2) 325 m
3) 425 m
4) 450 m
17. A car covers 60 km with a uniform speed of 120 kmph and the next 60 km with a uniform speed of 80 kmph . The total time taken by the car is \( \qquad \) .
1) 75 min
2) 60 min
3) 55 min
4) 80 min
18. A particle covers half of its journey with a constant speed of ' \( V \) ', half of the remaining part of journey with a constant speed of ' 2 V ' and the rest of the journey with a constant speed of ' 4 V '. Its average speed during the entire journey is \( \qquad \) .
1) 4 V
2) 3 V
3) \( \frac{16}{11} \mathrm{~V} \)
4) 11 V
19. A particle moving in a straight line covers half of the distance with a speed of \( 3 \mathrm{~m} / \mathrm{s} \). the other half is covered in two equal time intervals with a speed of \( 4.5 \mathrm{~m} / \mathrm{s} \) and \( 7.5 \mathrm{~m} / \mathrm{s} \) respectively, The average speed of the particle during its motion is \( \qquad \) .
1) \( 4 \mathrm{~m} / \mathrm{s} \)
2) \( 5 \mathrm{~m} / \mathrm{s} \)
3) \( 5.5 \mathrm{~m} / \mathrm{s} \)
4) \( 4.7 \mathrm{~m} / \mathrm{s} \)
20. A bullet shot from a rifle with a speed of \( 720 \mathrm{~m} / \mathrm{s} \). What time is required for the bullet to strike a target 3240 m away?
1) 4.5 S
2) 6.2 S
3) 5 S
4) 4.9 s
LEVEL-5
JEE MAIN
Single Answer Choice Type:
21. An aeroplane covers a certain distance at a speed of 240 kmph in 5 hours. To cover the same distance in 1 hour, with what speed it must travel?
1) 450 kmph
2) 750 kmph
3) 720 kmph
4) 600 kmph