The question asks for another name for buoyant force. Understanding the definition and common terminology associated with buoyancy is key to answering this question.
C) Upthrust — The buoyant force is indeed also known as upthrust. Both terms refer to the upward force exerted by a fluid that opposes the weight of an immersed object.
The value of acceleration due to gravity (\(g\)) on Earth is not constant. It varies with factors such as altitude, depth, and the shape of the Earth (latitude). The Earth is not a perfect sphere; it is an oblate spheroid, meaning it bulges at the equator and is flattened at the poles. This shape, combined with the Earth's rotation, causes variations in \(g\).
Correct Option: C) The value is almost negligible on the equator. While "negligible" might be a strong word, among the given options, this statement best reflects the fact that the value of \(g\) is minimum at the equator due to the combined effects of the Earth's bulge and its rotation. The reduction is significant enough to be considered the 'least' or 'almost negligible' in comparison to the poles.
The question refers to a significant astronomical observation involving the merger of giant black holes. This event is directly linked to a major scientific discovery that confirmed a key prediction of Einstein's theory of general relativity. We need to identify which of the given options represents this discovery.
Correct Option: B) 'Gravitational waves' were detected.
The question asks about the correctness of statements regarding gravitational force. We need to evaluate each statement based on Newton's Law of Universal Gravitation.
Combining these observations, the complete formula for Newton's Law of Universal Gravitation is:
\[ F = G \frac{m_1 m_2}{r^2} \]where \(G\) is the gravitational constant.
D) All the above. All three statements are correct descriptions of gravitational force and Newton's Law of Universal Gravitation.
This question tests the fundamental understanding of forces acting on an object immersed in a fluid, specifically upthrust (buoyant force) and weight (gravitational force).
Correct Option: D) Opposite direction. The weight of an object always acts downwards due to gravity, while the upthrust (buoyant force) exerted by a fluid always acts upwards, opposing the weight. Thus, they act in opposite directions.
To find the weight of an object on Earth, we need to use the formula that relates mass, gravity, and weight. Weight is the force exerted on an object due to gravity. The acceleration due to gravity on Earth is approximately \(9.8 \text{ m/s}^2\).
Weight (\(W\)) is calculated as the product of mass (\(m\)) and the acceleration due to gravity (\(g\)).
\[ W = m \times g \]The unit \(\text{kg} \cdot \text{m/s}^2\) is defined as Newton (\(\text{N}\)).
\[ W = 98 \text{ N} \]Correct Option: B) 98 Newton