Question
37. The table shows the times it took different animals to cover various distances.
MOTION OF ANIMALS
Animals: Gray fox, Gazelle, Rabbit, Cheetah, Giraffe, Antelope
Distance (km): 73, 68, 70, 85, 60, 93
Time (h): 1.05, 0.85, 1.25, 0.75, 1.15, 0.95
Which animal's speed is the greatest?
A) gray fox
B) cheetah
C) gazelle
D) rabbit
38. Which scenario best demonstrates an example of Newton's first law of motion?
a
A shopping cart accelerates when it is pushed.
b
A rocket lifts off from a launch pad.
c
A car passenger moves forward when a car suddenly stops.
d
A man pushes a canoe off the shore and into the water.
39. A radioisotope has a half-life of 7.5 hours. How many half lives have occured after 67.5 hours?
a
7 half-lives
b
8 half-lives
c
9 half-lives
d
10 half-lives
40. Column A
1. 20g of NaCl at 50°C
2. 45g KCl at 60°C
3. 70g of CaCl2 at 10°C
Column B
a. unsaturated
b. supersaturated
c. saturated
MOTION OF ANIMALS
Animals: Gray fox, Gazelle, Rabbit, Cheetah, Giraffe, Antelope
Distance (km): 73, 68, 70, 85, 60, 93
Time (h): 1.05, 0.85, 1.25, 0.75, 1.15, 0.95
Which animal's speed is the greatest?
A) gray fox
B) cheetah
C) gazelle
D) rabbit
38. Which scenario best demonstrates an example of Newton's first law of motion?
a
A shopping cart accelerates when it is pushed.
b
A rocket lifts off from a launch pad.
c
A car passenger moves forward when a car suddenly stops.
d
A man pushes a canoe off the shore and into the water.
39. A radioisotope has a half-life of 7.5 hours. How many half lives have occured after 67.5 hours?
a
7 half-lives
b
8 half-lives
c
9 half-lives
d
10 half-lives
40. Column A
1. 20g of NaCl at 50°C
2. 45g KCl at 60°C
3. 70g of CaCl2 at 10°C
Column B
a. unsaturated
b. supersaturated
c. saturated
Answers
Answered by
GPT-4o mini
Let's address each question one by one:
**37. The table shows the times it took different animals to cover various distances.**
To find the speed of each animal, we can use the formula:
\[
\text{Speed} = \frac{\text{Distance}}{\text{Time}}
\]
Now, let's calculate the speed for each animal:
1. Gray fox:
- Distance = 73 km, Time = 1.05 h
- Speed = \( \frac{73}{1.05} \approx 69.52 \) km/h
2. Cheetah:
- Distance = 85 km, Time = 0.75 h
- Speed = \( \frac{85}{0.75} \approx 113.33 \) km/h
3. Gazelle:
- Distance = 68 km, Time = 0.85 h
- Speed = \( \frac{68}{0.85} \approx 80.00 \) km/h
4. Rabbit:
- Distance = 70 km, Time = 1.25 h
- Speed = \( \frac{70}{1.25} \approx 56.00 \) km/h
Now we compare the speeds:
- Gray fox: 69.52 km/h
- Cheetah: 113.33 km/h
- Gazelle: 80.00 km/h
- Rabbit: 56.00 km/h
The greatest speed is that of the **Cheetah** (113.33 km/h).
**Answer: B) cheetah**
---
**38. Which scenario best demonstrates an example of Newton's first law of motion?**
Newton's first law states that an object at rest stays at rest, and an object in motion stays in motion unless acted upon by a net external force.
The best example is:
**c) A car passenger moves forward when a car suddenly stops.**
This demonstrates Newton's first law because the passenger continues in motion due to inertia until a force (the seatbelt, for example) acts on them.
**Answer: c) A car passenger moves forward when a car suddenly stops.**
---
**39. A radioisotope has a half-life of 7.5 hours. How many half-lives have occurred after 67.5 hours?**
To find the number of half-lives that have occurred, we divide the total time by the half-life:
\[
\frac{67.5 \text{ hours}}{7.5 \text{ hours/half-life}} = 9 \text{ half-lives}
\]
**Answer: c) 9 half-lives**
---
**40. Column A (the solubility scenarios) and Column B (solubility conditions):**
To classify the given amounts of solutes with respect to their saturation level:
1. **20g of NaCl at 50°C**
- Generally, NaCl is soluble in water. This amount would likely be unsaturated, as 20g is typically below the saturation point at 50°C.
2. **45g KCl at 60°C**
- KCl’s solubility increases with temperature. 45g may be near or below the saturation limit at 60°C, depending on specific solubility data. Generally considered unsaturated but could be close to saturated.
3. **70g of CaCl2 at 10°C**
- Calcium chloride is very soluble, and at 10°C, 70g would likely saturate or exceed most solubility limits. This is typically considered supersaturated if dissolved.
Based on the data, we classify them:
1 → a. unsaturated
2 → a. unsaturated (or close to saturated, but typically unsaturated)
3 → b. supersaturated
**Answer: 1a, 2a, 3b** (depending on detailed solubility data)
Let me know if you need additional information or clarifications!
**37. The table shows the times it took different animals to cover various distances.**
To find the speed of each animal, we can use the formula:
\[
\text{Speed} = \frac{\text{Distance}}{\text{Time}}
\]
Now, let's calculate the speed for each animal:
1. Gray fox:
- Distance = 73 km, Time = 1.05 h
- Speed = \( \frac{73}{1.05} \approx 69.52 \) km/h
2. Cheetah:
- Distance = 85 km, Time = 0.75 h
- Speed = \( \frac{85}{0.75} \approx 113.33 \) km/h
3. Gazelle:
- Distance = 68 km, Time = 0.85 h
- Speed = \( \frac{68}{0.85} \approx 80.00 \) km/h
4. Rabbit:
- Distance = 70 km, Time = 1.25 h
- Speed = \( \frac{70}{1.25} \approx 56.00 \) km/h
Now we compare the speeds:
- Gray fox: 69.52 km/h
- Cheetah: 113.33 km/h
- Gazelle: 80.00 km/h
- Rabbit: 56.00 km/h
The greatest speed is that of the **Cheetah** (113.33 km/h).
**Answer: B) cheetah**
---
**38. Which scenario best demonstrates an example of Newton's first law of motion?**
Newton's first law states that an object at rest stays at rest, and an object in motion stays in motion unless acted upon by a net external force.
The best example is:
**c) A car passenger moves forward when a car suddenly stops.**
This demonstrates Newton's first law because the passenger continues in motion due to inertia until a force (the seatbelt, for example) acts on them.
**Answer: c) A car passenger moves forward when a car suddenly stops.**
---
**39. A radioisotope has a half-life of 7.5 hours. How many half-lives have occurred after 67.5 hours?**
To find the number of half-lives that have occurred, we divide the total time by the half-life:
\[
\frac{67.5 \text{ hours}}{7.5 \text{ hours/half-life}} = 9 \text{ half-lives}
\]
**Answer: c) 9 half-lives**
---
**40. Column A (the solubility scenarios) and Column B (solubility conditions):**
To classify the given amounts of solutes with respect to their saturation level:
1. **20g of NaCl at 50°C**
- Generally, NaCl is soluble in water. This amount would likely be unsaturated, as 20g is typically below the saturation point at 50°C.
2. **45g KCl at 60°C**
- KCl’s solubility increases with temperature. 45g may be near or below the saturation limit at 60°C, depending on specific solubility data. Generally considered unsaturated but could be close to saturated.
3. **70g of CaCl2 at 10°C**
- Calcium chloride is very soluble, and at 10°C, 70g would likely saturate or exceed most solubility limits. This is typically considered supersaturated if dissolved.
Based on the data, we classify them:
1 → a. unsaturated
2 → a. unsaturated (or close to saturated, but typically unsaturated)
3 → b. supersaturated
**Answer: 1a, 2a, 3b** (depending on detailed solubility data)
Let me know if you need additional information or clarifications!