Answer: a = 0.4m/s^2 - 9.8*c where c is the coefficient of kinetic friction of the surface
Explanation: We know that, by the second Newton's law, a = F/m
where a is the acceleration, F is the net force and m is the mass of the object.
Then, if the surface is frictionless, the total force applied in the object is 10N, and the mass of the object is 25kg, so the acceleration is:
a =10N/25kg = 0.4m/s^2.
But if the surface is frictional, there will be a force of friction applied in the mass (this depends on the coefficient of friction and the weight of the mass), this means that the acceleration will be reduced.
If = -(9.8*25)*c
where c is a number that is bigger than 0 and smaller than 1, is called the coefficient of kinetic friction.
So the total force is now:
F = (10 - 9.8*25*c)
Then, the acceleration in a frictional surface is equal to:
a = (10 - 9.8*25*c)/25 = 0.4m/s^2 - 9.8*c
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hope this helps
Answer:
Gravity acts to pull the object down.
The object’s inertia carries it forward.
The path of the object is curved.
Explanation:
The motion of a projectile consists of two separate motions:
- A uniform motion along the horizontal direction, where the velocity is constant; since there are no forces along this direction, the velocity does not change, and so the object continues its motion for inertia --> so, the statement "The object’s inertia carries it forward" is true.
- A uniformly accelerated motion along the vertical direction, with a constant downward acceleration (g=9.8 m/s^2, acceleration due to gravity). So, the vertical velocity changes, due to the presence of the gravity that acts to pull the object down.
- As a result of the combination of these two motions, the object follows a curved path (in particular, it is a parabolic path).
Answer:
a. If an object's speed is constant, then its acceleration must be zero.
FALSE
As we know that acceleration is defined as the rate of change in velocity
so we can not say anything about the acceleration when speed is given to as and no information is given about velocity
b. If an object's acceleration is zero, then its speed must be constant.
TRUE
As we know that acceleration is defined as the rate of change in velocity
Since we know that if acceleration is 0 then velocity must be constant and hence speed is also constant
c. If an object's velocity is constant, then its speed must be constant.
TRUE
Since velocity is constant then it shows that its magnitude and direction both are constant so its speed is also constant.
d. If an object's acceleration is zero, its velocity must be constant.
TRUE
As we know that acceleration is defined as the rate of change in velocity
Since we know that if acceleration is 0 then velocity must be constant
e. If an object's speed is constant, then its velocity must be constant.
FALSE
Speed is just the magnitude so we can not say about its direction and hence if speed is constant then velocity may or may not change
