Dynamics — Quiz 4

Questions in this quiz (10)

1. Two engine-driven boats are racing with velocities of 12 m/s and 6 m/s. Their accelerations are 2 m/s² and 4 m/s², respectively. If the two boats reach the finish line at the same time, how long (sec) did boats participate in the race?

   • 6
   • 10
   • 12
   • 14

2. A baseball moving horizontally with a velocity of 40 m/s is hit by a bat at a right angle to the ball velocity. As a result, the ball acquires a velocity of 50 m/s. The batting velocity is most nearly:

   • 20 m/s
   • 25 m/s
   • 30 m/s
   • 35 m/s

3. A man swims at a right angle to the current of a river and meets the opposite bank 600 m from the starting point. If he swims at twice the speed of the current, the width of the river (m) is most nearly:

   • 600
   • 900
   • 1,200
   • 1,500

4. A man can swim directly across a river of 120 m width in 5 minutes if there is no current. He takes 6 minutes to cross directly when there is current. The velocity (m/min) of the current is most nearly:

   • 12
   • 16
   • 20
   • 24

5. A vehicle moving with a velocity of 60 km/h touches a straight highway and comes to rest in 250 m. If the retardation is uniform, the required time (sec) to stop is most nearly:

   • 30
   • 35
   • 42
   • 50

6. A train traveling at 72 km/h is stopped at the next station in 12 sec by applying brakes. Most nearly, at what distance from the next station were the brakes applied?

   • 100 m
   • 120 m
   • 140 m
   • 160 m

7. A particle moving along a straight line with uniform acceleration covers a distance of 80 cm at the 10th second, and a distance of 140 cm at the 18th second. If the acceleration of the particle is 5 cm/s², the initial velocity (cm/sec) is most nearly:

   • 41.3
   • 52.5
   • 63.7
   • 67.4

8. A helicopter moving horizontally at a height of 400 m with a speed of 120 m/s drops a package. Neglecting air resistance, the velocity (m/s) of the package after 4 sec is most nearly:

   • 126
   • 135
   • 142
   • 150

9. A projectile with an initial velocity of 60 m/s is launched at an angle of 30° with the horizontal. The horizontal distance (m) traveled by the projectile is most nearly:

   • 220
   • 260
   • 318
   • 360

10. The position of a drone is represented as (x, y) = (0.4t³, 0.3t²) where x and y are in meters and t is in seconds. The acceleration (m/s²) of the drone after traveling 4 sec is most nearly:

    • 7.2
    • 8.4
    • 9.6
    • 10.8