NEET · Physics · Gravitation doubts
11 doubts found
What does “Universal law of gravitation” actually mean in Gravitation, and why does it matter for NEET?
every two masses attract with F = G·m₁m₂/r² along the line joining them.
I keep getting “Universal law of gravitation” questions wrong in Gravitation. What's the trap?
forgetting the force depends on 1/r² — doubling the distance quarters the force.
What does “Acceleration due to gravity g” actually mean in Gravitation, and why does it matter for NEET?
g = GM/R² at a planet's surface; it decreases with both altitude and depth.
I keep getting “Acceleration due to gravity g” questions wrong in Gravitation. What's the trap?
treating g as a fixed 9.8 everywhere, including in orbit.
What does “Gravitational potential energy” actually mean in Gravitation, and why does it matter for NEET?
for large distances PE = −GMm/r (negative, zero at infinity), not mgh.
I keep getting “Gravitational potential energy” questions wrong in Gravitation. What's the trap?
using mgh far from the surface, where it no longer holds.
What does “Escape velocity” actually mean in Gravitation, and why does it matter for NEET?
the minimum speed to leave a planet's gravity, v = √(2GM/R) ≈ 11.2 km/s for Earth.
I keep getting “Escape velocity” questions wrong in Gravitation. What's the trap?
confusing it with orbital velocity.
What does “Kepler's laws” actually mean in Gravitation, and why does it matter for NEET?
orbits are ellipses; a planet sweeps equal areas in equal times; T² ∝ r³.
I keep getting “Kepler's laws” questions wrong in Gravitation. What's the trap?
assuming orbital speed is constant — planets move faster near the Sun.
What is the difference between orbital velocity and escape velocity?
Orbital velocity keeps a satellite in a circular orbit; escape velocity (√2 times larger) lets it leave gravity forever.