A projectile of mass m is fired straight upward from the surface of an airless planet of radius R and mass M with an initial spe
1 answer:
Answer:
K = G Mm / 9R
Explanation:
Expression for escape velocity V_e =
Kinetic energy at the surface = 1/2 m V_e ²
= 1/2 x m x 2GM/R
GMm/R
Potential energy at the surface
= - GMm/R
Total energy = 0
At height 9R ( 8R from the surface )
potential energy
= - G Mm / 9R
Kinetic energy = K
Total energy will be zero according to law of conservation of mechanical energy
so
K - G Mm / 9R = 0
K = G Mm / 9R
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Answer:
By a positive charge
Explanation:
The electric field is a vector consisting of a magnitude and a direction.
- The magnitude of the field depends on the configuration of the field: for example, for the electric field produced by a single point charge, it is
where k is the Coulomb's constant, q is the magnitude of the charge, r is the distance from the charge.
- The direction of the field corresponds to the force that a positive charge would feel in that field. For example, the electric field produced by a single-point positive charge points away from the charge itself: this is because a positive test charge placed in this field would feel a repulsive force, so it would move away from the source of the field. Vice-versa, the electric field produced by a single-point negative charge points towards the charge itself: this is because a positive test charge placed in this field would feel an attractive force, so it would move towards the source of the field.