If no other forces act on the object, according to Newton’s first law, the spacecraft will continue moving at a constant velocity, assuming that a planet or something with large mass doesn’t cross its path. Forces are not required to continue the motion of an object on a frictionless plane at a constant rate.
Answer:
5.3 hours
Explanation:
(3180 km) / (600 km/h) = 5.3 hours
Answer:
1.63 
Explanation:
The equation 
would be used where:
g = acceleration due to gravity
G = universal gravitational constant (6.67408 × 
)
M = mass
R = radius.
assuming the values following both 10s of the mass and radius are their exponents, which is a little confusing, the values given would simply be substituted.
Anyone can correct me if I'm wrong.
Answer:
From question (a) and (b) the pendulum motion is perpendicular to the force so the normal force will do no work and the tension in the string of the pendulum will not work
And 
so
c
An example will be a where a stone is attached to the end of a string and is made to move in a circular motion while keeping the other end of the string in a fixed position
d
A dog walking along a surface which has friction, here the frictional force would acting in the direction of the motion and this would do positive work
Explanation:
.
.
.