Acceleration

Answer Key - Grade 11 Science Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   Ari times a car on a straight road. Its speed goes from 36 km/h to 90 km/h in 6 s. What is its acceleration in m/s²?

   2.5 m/s²
2. 2.

   Bo clocks a scooter on a straight path. Its speed goes from 36 km/h to 72 km/h in 5 s. What is its acceleration in m/s²?

   2 m/s²
3. 3.

   Esme rides a train that speeds up on straight track, from 18 km/h to 108 km/h in 20 s. What is its acceleration in m/s²?

   1.25 m/s²
4. 4.

   In the velocity-time graph, the lines for carts A and B cross at 4 s. Which statement is true then, Jun?

   • Equal velocities, 10 m/s; A is speeding up and B is slowing
   • Equal accelerations, since the lines meet
   • Both carts have a = 0, since their velocities are equal
   • B has the larger acceleration, since it started faster
5. 5.

   West is negative. In the graph, a cart climbs from −8 m/s to 0 m/s in 4 s. What are its acceleration and motion, Kira?

   • +2 m/s², and the cart is speeding up
   • +2 m/s², and the cart is slowing down
   • 0 m/s², since the line ends at rest
   • −2 m/s², since its velocity values are negative
6. 6.

   A car is rated 0 to 60 mph in 3.0 s and a truck 0 to 60 mph in 6.0 s. What does that say, Milo?

   • The car has twice the acceleration of the truck
   • The two have the same acceleration, since both reach 60 mph
   • The car has twice the speed of the truck
   • The truck has twice the acceleration, since it takes twice as long
7. 7.

   A cart has a = 4 m/s² and v = 3 m/s when the clock reads 2 s. What is v when the clock reads 3 s, Noah?

   • 4 m/s, because that is the acceleration
   • 15 m/s, because 4 m/s² acts for 3 s
   • 12 m/s, because 3 × 4
   • 7 m/s: one more second adds 4 m/s
8. 8.

   A car rounds a bend at a steady 20 m/s. Is it accelerating, Pia?

   • Yes: any moving object is accelerating
   • No: acceleration means speeding up, not turning
   • Yes: the direction changes, so v changes
   • No: its speed is steady, so a is zero
9. 9.

   West is negative. A train has v = −12 m/s and a = +3 m/s². What is it doing, Tala?

   • Slowing down; it stops after 4 s
   • Speeding up eastward, since a is positive
   • Speeding up, since a is positive
   • Slowing down; it stops after 36 s
10. 10.

    Up is positive. A tossed ball is at its top, v = 0 for an instant. What is a then, Zee?

    • a = +9.8 m/s², since it is rising
    • a = 0, since the up and down motion cancel
    • a = 0, since the ball has stopped
    • a = −9.8 m/s²: gravity still changes v