Alunar lander is making its descent to moon base i. the lander descends slowly under the retro-thrust of its descent engine. the engine is cut off when the lander is h = 5.5 m above the surface and has a downward speed of 0.8 m/s. with the engine off, the lander is in free fall. what is the speed of the lander just before it touches the surface? the acceleration due to gravity on the moon is 1.6 m/s2.

The speed of the lander just before it touches the surface is about 4.3 m/s

Acceleration is rate of change of velocity.

where:

a = acceleration ( m/s² )

v = final velocity ( m/s )

u = initial velocity ( m/s )

t = time taken ( s )

d = distance ( m )

Let us now tackle the problem!

Given:

position of the lander above the surface = h = 5.5 m

initial downward speed of lander = u = 0.8 m/s

acceleration due to gravity on the moon = g = 1.6 m/s²

Asked:

final speed of the lander = v = ?

Solution:

The speed of the lander just before it touches the surfacet is about 4.3 m/s

Grade: High School

Subject: Physics

Chapter: Kinematics

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