Look at the distance vs. time graph of an object in motion.
Which statement describes the motion of the object for the first 10 seconds?
- A. The object is moving at a constant speed.
- B. The object is doubling its speed every two seconds.
- C. The object is increasing its height.
- D. The object is accelerating.
Correct Answer & Rationale
Correct Answer: D
The motion of the object for the first 10 seconds indicates that it is accelerating, meaning its speed is increasing over time. Option A is incorrect because constant speed implies no change in velocity, which contradicts the evidence of acceleration. Option B suggests a specific pattern of doubling speed, which is not necessarily true without further information on the object's velocity changes. Option C, while it may imply upward motion, does not capture the essential aspect of acceleration, which is a change in speed rather than just height.
The motion of the object for the first 10 seconds indicates that it is accelerating, meaning its speed is increasing over time. Option A is incorrect because constant speed implies no change in velocity, which contradicts the evidence of acceleration. Option B suggests a specific pattern of doubling speed, which is not necessarily true without further information on the object's velocity changes. Option C, while it may imply upward motion, does not capture the essential aspect of acceleration, which is a change in speed rather than just height.
Other Related Questions
Scientists have estimated the mass of the object that caused the Tunguska Event at 5 x 10^12 kilograms (kg). If the object was a comet in which 1% of total mass was ammonia, how much ammonia did the comet contain? kg
Correct Answer & Rationale
Correct Answer: 5x10^10
To find the mass of ammonia in the comet, we calculate 1% of the total mass (5 x 10^12 kg). This is done by multiplying the total mass by 0.01: 5 x 10^12 kg × 0.01 = 5 x 10^10 kg. This calculation confirms that the comet contained 5 x 10^10 kg of ammonia. Other options may result from incorrect calculations, such as misunderstanding the percentage or misapplying the multiplication. For instance, using 0.1 instead of 0.01 would yield an answer ten times larger, while failing to convert the percentage to a decimal would also lead to an incorrect figure.
To find the mass of ammonia in the comet, we calculate 1% of the total mass (5 x 10^12 kg). This is done by multiplying the total mass by 0.01: 5 x 10^12 kg × 0.01 = 5 x 10^10 kg. This calculation confirms that the comet contained 5 x 10^10 kg of ammonia. Other options may result from incorrect calculations, such as misunderstanding the percentage or misapplying the multiplication. For instance, using 0.1 instead of 0.01 would yield an answer ten times larger, while failing to convert the percentage to a decimal would also lead to an incorrect figure.
What statement describes one or more needed changes to this experiment that would allow the experimenter to draw a valid conclusion?
- A. Salt water should have been used to make the ice cubes for the cup of salt water.
- B. The time for ice cubes to melt should have been measured in minutes.
- C. At the beginning, both cups should have contained the same mass of water at the same temperature.
- D. The energy released should have been measured, not calculated.
Correct Answer & Rationale
Correct Answer: C
Option C highlights the necessity for both cups to start with the same mass of water at the same temperature to ensure a fair comparison. This control eliminates variables that could skew results, allowing for a valid conclusion about the melting rates of ice cubes in different solutions. Option A is incorrect because using salt water to make ice cubes would not provide relevant data on how the ice behaves in fresh versus salt water. Option B is not a change that affects the experimental validity; measuring time in minutes is appropriate, but the key is ensuring conditions are equal. Option D suggests a measurement method change, but calculating energy based on temperature changes is acceptable in this context.
Option C highlights the necessity for both cups to start with the same mass of water at the same temperature to ensure a fair comparison. This control eliminates variables that could skew results, allowing for a valid conclusion about the melting rates of ice cubes in different solutions. Option A is incorrect because using salt water to make ice cubes would not provide relevant data on how the ice behaves in fresh versus salt water. Option B is not a change that affects the experimental validity; measuring time in minutes is appropriate, but the key is ensuring conditions are equal. Option D suggests a measurement method change, but calculating energy based on temperature changes is acceptable in this context.
According to the passage, which statement about hybrid lovebirds is true?
- A. Nest-building behavior can be used to determine evolutionary relationships between lovebird species.
- B. Hybrid lovebirds use nest-building material in ways they learn from the parents.
- C. Nest-building behavior in hybrid lovebirds is a mixture of the parents' behaviors.
- D. Hybrid lovebirds build complex nests using smaller pieces of nest-building material.
Correct Answer & Rationale
Correct Answer: C
Hybrid lovebirds exhibit nest-building behavior that reflects a combination of their parents' distinct styles, showcasing the influence of both species in their hybrid traits. This blending of behaviors illustrates how hybridization can lead to unique adaptations. Option A is incorrect as the passage does not indicate that nest-building behavior is a reliable indicator of evolutionary relationships. Option B is misleading; while learning from parents is important, the focus is on the integration of behaviors rather than direct imitation. Option D is inaccurate; the passage does not mention the complexity of nests or the size of materials used, making this statement unsupported.
Hybrid lovebirds exhibit nest-building behavior that reflects a combination of their parents' distinct styles, showcasing the influence of both species in their hybrid traits. This blending of behaviors illustrates how hybridization can lead to unique adaptations. Option A is incorrect as the passage does not indicate that nest-building behavior is a reliable indicator of evolutionary relationships. Option B is misleading; while learning from parents is important, the focus is on the integration of behaviors rather than direct imitation. Option D is inaccurate; the passage does not mention the complexity of nests or the size of materials used, making this statement unsupported.
The chemical composition and energy density of four fuels are shown in the table. Ethane, which has a chemical composition of C2H6, is also a fuel. What is the predicted energy density of ethane?
- A. 45 MJ/kg
- B. 42 MJ/kg
- C. 52 MJ/kg
- D. 48 MJ/kg
Correct Answer & Rationale
Correct Answer: C
To determine the predicted energy density of ethane (C2H6), one can analyze its molecular structure and compare it to the energy densities of similar hydrocarbons listed in the table. Ethane, being an alkane, typically has a higher energy density due to its saturated carbon-hydrogen bonds. Option A (45 MJ/kg) is lower than expected for alkanes of similar size. Option B (42 MJ/kg) underestimates the energy density, as it does not align with the general trend for hydrocarbons. Option D (48 MJ/kg) is closer but still below the typical range for ethane. Thus, option C (52 MJ/kg) aligns with the expected energy density for ethane, reflecting its molecular composition and energy potential.
To determine the predicted energy density of ethane (C2H6), one can analyze its molecular structure and compare it to the energy densities of similar hydrocarbons listed in the table. Ethane, being an alkane, typically has a higher energy density due to its saturated carbon-hydrogen bonds. Option A (45 MJ/kg) is lower than expected for alkanes of similar size. Option B (42 MJ/kg) underestimates the energy density, as it does not align with the general trend for hydrocarbons. Option D (48 MJ/kg) is closer but still below the typical range for ethane. Thus, option C (52 MJ/kg) aligns with the expected energy density for ethane, reflecting its molecular composition and energy potential.