9. Amelia swims at an average speed of 8 meters per second, how long will it take her to complete a race of 600 meters length?

a
75 seconds
b
1.3 seconds
c
4800 seconds
d
48 seconds

10. The table shows the times it took different animals to cover various distances.

MOTION OF ANIMALS
Animals Distance (km) Time (h)
Gray fox 73 1.05
Gazelle 68 0.85
Rabbit 70 1.25
Cheetah 85 0.75
Giraffe 60 1.15
Antelope 93 0.95


Which animal's speed is the greatest?

a
gazelle
b
rabbit
c
gray fox
d
cheetah

12. Balance the following the chemical equation: _ Mg + _ F2 - _ MgF2
A) 1:1:2
B) 1:1:1
C) 1:2:1
D) 2:1:1

13. An object originally at rest is uniformly accelerated to a speed of 8.0 meters per second in 2.0 seconds. What is the acceleration of the object?
acceleration=\frac{v_{final}-v_{initial} {time}

a
0.25 m/s2
b
4.0 m/s2
c
10. m/s2
d
16 m/s2

14. What is the difference between speed and velocity?

a
Velocity has distance.

b
Velocity has time.
c
Velocity has direction.
d
Velocity has weight.

15. What is the difference between a vector and a scalar?

a
A vector measurement contains a direction and magnitude, a scalar measurement only contains a magnitude
b
A vector measurement is required for distance, a scalar measurement is required for displacement
c
A vector is only used in measuring forces, a scalar is only used in measuring mass
d
A vector is only measured in SI units, where scalars are only measured in US Customary units

1 answer

Sure! Here are the answers to your questions:

  1. To find the time it takes Amelia to complete a 600-meter race at a speed of 8 meters per second, you use the formula: \[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} = \frac{600 \text{ m}}{8 \text{ m/s}} = 75 \text{ seconds} \] Answer: a) 75 seconds

  2. To find the speed of each animal, you can calculate speed using the formula: \[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} \]

  • Gray fox: \( \frac{73 \text{ km}}{1.05 \text{ h}} \approx 69.52 \text{ km/h} \)
  • Gazelle: \( \frac{68 \text{ km}}{0.85 \text{ h}} \approx 80.00 \text{ km/h} \)
  • Rabbit: \( \frac{70 \text{ km}}{1.25 \text{ h}} \approx 56.00 \text{ km/h} \)
  • Cheetah: \( \frac{85 \text{ km}}{0.75 \text{ h}} \approx 113.33 \text{ km/h} \)
  • Giraffe: \( \frac{60 \text{ km}}{1.15 \text{ h}} \approx 52.17 \text{ km/h} \)
  • Antelope: \( \frac{93 \text{ km}}{0.95 \text{ h}} \approx 97.89 \text{ km/h} \)

The cheetah has the greatest speed. Answer: d) cheetah

  1. Balancing the equation \( \text{Mg} + \text{F}_2 \rightarrow \text{MgF}_2 \): Each Mg atom combines with two F atoms. Therefore, the balanced equation is: \[ 1 \text{ Mg} + 1 \text{ F}_2 \rightarrow 1 \text{ MgF}_2 \] So, the coefficients are 1:1:1. Answer: B) 1:1:1

  2. To calculate acceleration: \[ \text{Acceleration} = \frac{v_{\text{final}} - v_{\text{initial}}}{\text{Time}} = \frac{8.0 \text{ m/s} - 0 \text{ m/s}}{2.0 \text{ s}} = \frac{8.0 \text{ m/s}}{2.0 \text{ s}} = 4.0 \text{ m/s}^2 \] Answer: b) 4.0 m/s²

  3. The difference between speed and velocity is that velocity includes direction while speed does not. Answer: c) Velocity has direction.

  4. A vector measurement contains both direction and magnitude, while a scalar measurement contains only magnitude. Answer: a) A vector measurement contains a direction and magnitude, a scalar measurement only contains a magnitude