10. which graph shows constant acceleration?
a position - time straight line
b velocity - time straight line
c velocity - time curve
d position - time curve
11. an object moves with constant acceleration. which quantity changes uniformly?
a velocity
b position
c acceleration
d force
12. a ball is thrown upward. at the highest point, which is true?
a velocity is zero
b acceleration is zero
c force is zero
d displacement is zero
13. an object moves in a circle at constant speed. which is true?
a velocity is constant
b acceleration is zero
c net force is zero
d acceleration is toward center
14. a velocity - time graph has a slope of 2 m/s². what does this indicate?
a velocity
b acceleration
c displacement
d force

Question

Accepted Answer

### Question 10
# Explanation:
## Step1: Recall motion graph concepts
In kinematics, acceleration is the rate of change of velocity ($a = \frac{\Delta v}{\Delta t}$). For a position - time graph, the slope is velocity ($v=\frac{\Delta x}{\Delta t}$). A straight - line position - time graph means constant velocity (zero acceleration). A curved position - time graph means changing velocity (non - constant acceleration). For a velocity - time graph, the slope is acceleration ($a=\frac{\Delta v}{\Delta t}$). A straight - line velocity - time graph has a constant slope, so it means constant acceleration. A curved velocity - time graph has a changing slope, meaning non - constant acceleration.
## Step2: Analyze each option
- Option a: Position - time straight line means constant velocity (acceleration = 0, not constant non - zero acceleration in general, and if acceleration is zero, it is a special case of constant acceleration but the question is about showing constant acceleration. A straight - line position - time graph is more associated with constant velocity).
- Option b: Velocity - time straight line has a constant slope, so acceleration is constant. This is the correct graph for constant acceleration.
- Option c: Velocity - time curve has a changing slope, so acceleration is changing (non - constant).
- Option d: Position - time curve has a changing slope (velocity is changing), so acceleration is changing (non - constant).
# Answer:
b. Velocity - time straight line

### Question 11
# Explanation:
## Step1: Recall the definition of constant acceleration
Constant acceleration means $a=\frac{\Delta v}{\Delta t} = 	ext{constant}$. By rearranging, $\Delta v=a\Delta t$. Since $a$ is constant, the change in velocity ($\Delta v$) is proportional to the change in time ($\Delta t$), which means velocity changes uniformly (at a constant rate).
## Step2: Analyze other options
- Option b: Position changes according to $x = x_0+v_0t+\frac{1}{2}at^2$ (for constant acceleration). The change in position is not uniform (it is a quadratic function of time).
- Option c: Acceleration is constant, so it does not change.
- Option d: Force $F = ma$. If $a$ is constant and $m$ is constant (for a given object), force is constant, not changing.
# Answer:
a. Velocity

### Question 12
# Explanation:
## Step1: Analyze the motion of the ball thrown upward
When a ball is thrown upward, it is under the influence of gravity (neglecting air resistance). The acceleration due to gravity ($g$) acts downward throughout the motion. At the highest point, the ball stops moving upward and is about to start moving downward.
## Step2: Analyze each option
- Option a: At the highest point, the ball's velocity in the upward direction becomes zero (it has no speed in the upward or downward direction at that instant before starting to fall). This is correct.
- Option b: Acceleration is equal to $g$ (acceleration due to gravity) and is not zero.
- Option c: Force $F = mg$ (due to gravity) and is not zero.
- Option d: Displacement is the distance from the starting point. At the highest point, the displacement is maximum (not zero).
# Answer:
a. Velocity is zero

### Question 13
# Explanation:
## Step1: Recall circular motion concepts
When an object moves in a circle at constant speed, it is in uniform circular motion. Velocity is a vector quantity, and in circular motion, the direction of velocity is tangent to the circle. Since the direction of velocity is constantly changing, velocity is not constant.
## Step2: Analyze acceleration and net force
According to Newton's second law, $F_{net}=ma$. In uniform circular motion, there must be a net force (centripetal force) acting towards the center of the circle to change the direction of velocity. The acceleration (centripetal acceleration) is given by $a=\frac{v^{2}}{r}$ (or $a = \omega^{2}r$) and is directed towards the center of the circle.
## Step3: Analyze each option
- Option a: Velocity direction changes, so velocity is not constant.
- Option b: Acceleration is non - zero (centripetal acceleration towards the center).
- Option c: Net force is non - zero (centripetal force towards the center).
- Option d: Acceleration is toward the center (centripetal acceleration). This is correct.
# Answer:
d. Acceleration is toward center

### Question 14
# Explanation:
## Step1: Recall the meaning of slope in a velocity - time graph
The slope of a velocity - time graph is defined as $	ext{slope}=\frac{\Delta v}{\Delta t}$. From the definition of acceleration, $a=\frac{\Delta v}{\Delta t}$. So the slope of a velocity - time graph is equal to the acceleration.
## Step2: Analyze other options
- Option a: Velocity is the y - axis variable in a velocity - time graph, not related to the slope.
- Option c: Displacement is the area under the velocity - time graph, not related to the slope.
- Option d: Force $F = ma$. The slope gives acceleration, and force is related to acceleration but the slope itself represents acceleration.
# Answer:
b. Acceleration

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QUESTION IMAGE

Question

Explanation:

Question 10

Step1: Recall motion graph concepts

Step2: Analyze each option

Step1: Recall the definition of constant acceleration

Step2: Analyze other options

Step1: Analyze the motion of the ball thrown upward

Step2: Analyze each option

Answer:

Question 11