Constant acceleration is when the velocity changes the same amount in every equal time period. For example : 9.8 m/s^2
Instantaneous acceleration is the rate at which velocity changes at a specific instant in time. For example: at one point it might be 8m/s^2 and at another point 13m/s^2
Answer: The weight of a 72.0 kg astronaut on the Moon is 117.36 N.
Explanation:
Mass of the astronaut on the moon , m= 72 kg
Acceleration due to gravity on moon,g = 1.63 
According to Newton second law of motion: F = ma
This will changes to = Weight = mass × g

The weight of a 72.0 kg astronaut on the Moon is 117.36 N.
Answer:
F = 800N
the magnitude of the average force exerted on the wall by the ball is 800N
Explanation:
Applying the impulse-momentum equation;
Impulse = change in momentum
Ft = m∆v
F = (m∆v)/t
Where;
F = force
t = time
m = mass
∆v = v2 - v1 = change in velocity
Given;
m = 0.80 kg
t = 0.050 s
The ball strikes the wall horizontally with a speed of 25 m/s, and it bounces back with this same speed.
v2 = 25 m/s
v1 = -25 m/s
∆v = v2 - v1 = 25 - (-25) m/s = 25 +25 = 50 m/s
Substituting the values;
F = (m∆v)/t
F = (0.80×50)/0.05
F = 800N
the magnitude of the average force exerted on the wall by the ball is 800N
Answer:
Speed is a "scalar" quantity
(C) is the correct answer
An object could travel at 10 m/s to some point and then return to the origin at 10 m/s for an average speed of 10 m/s, however it's displacement over that time would be zero for a net velocity of zero.
Answer:
Explanation:
1 ) the volume of helium in the balloon when fully inflated
= 4/3 π R³
= 4/3 x 3.14 x 5.3³
= 623.3 m³
2 ) force of gravity on the entire system ,but with no people
= (mass of the empty balloon and basket + mass of helium )x g
=( 129 + 623.3 x.18 )x 9.8
= 2363.7 N
3 ) magnitude of the buoyant force on the entire system (but with no people )
( Volume of empty balloon + basket + volume of helium ) density of air x g
( 0.057 + 623.3 ) x 1.23 x 9.8
= 7513.94 N
4 ) magnitude of the force of gravity on each person
Mass of each person x g
= 71 x 9.8
= 695.8 N