Question

name: ______________ test # 2b

1. which of the following statements correctly describes the motion of an object shown by the graph?

graph: d vs t, straight line from origin
a) the object has constant velocity
b) the object has increasing velocity
b) the object has non-uniform motion
d) the object has increasing acceleration

1. which one of the following statements correctly describes the motion of an object depicted by the graph ?

graph: v vs t, straight line from origin
a) the object is moving at constant velocity
b)the object is accelerating uniformly
c) the objects velocity is decreasing
d)the object is in uniform motion

1. a hockey player gliding along the ice at a velocity of 1.0 m/s accelerates at 2.0 m/s² for 3.0 s. his final velocity is:

a) 7.0 m/s
b) 6.0 m/s
c) 5.0 m/s
d) 3.0 m/s

1. a go cart moving at 60 m/s accelerates uniformly and travels a distance of 200 m in 2.6 s. what is the cars acceleration?

a) 13 m/s²
b) 17 m/s²
c) 23 m/s²
d) 30 m/s²

1. a musket ball covers the 25 m between the gun and the target in 0.35 s. the bullet embeds itself in the target, coming to a halt in 0.524 s. at what rate does the bullet decelerate?

a) -140 m/s²
b) -37 m/s²
c) 11 m/s²
d) 37 m/s²
e) 140 m/s²

Explanation:

Question 4

The graph is a distance - time ($d - t$) graph with a straight line through the origin. In a $d - t$ graph, the slope represents velocity. A straight line means the slope (velocity) is constant. Option B is wrong as velocity is constant, not increasing. Option C is wrong as non - uniform motion would have a non - constant slope. Option D is wrong as acceleration is zero (constant velocity) and not increasing.

The graph is a velocity - time ($v - t$) graph with a straight line through the origin. In a $v - t$ graph, the slope represents acceleration. A straight line with a positive slope means the velocity is increasing at a constant rate, so the object is accelerating uniformly. Option A is wrong as velocity is changing. Option C is wrong as velocity is increasing. Option D is wrong as uniform motion has constant velocity (a horizontal line in $v - t$ graph).

Step1: Recall the kinematic equation

We use the equation $v = u+at$, where $u$ is the initial velocity, $a$ is the acceleration, $t$ is the time and $v$ is the final velocity.

Step2: Substitute the values

Given $u = 1.0\ m/s$, $a=2.0\ m/s^{2}$, $t = 3.0\ s$.
Substitute into the equation: $v=1.0+(2.0\times3.0)=1.0 + 6.0=7.0\ m/s$? Wait, no, wait. Wait, $u = 1.0\ m/s$, $a = 2.0\ m/s^{2}$, $t=3.0\ s$. $v=u + at=1+2\times3=1 + 6 = 7$? But wait, let's check again. Wait, maybe I made a mistake. Wait, $u = 1.0$, $a = 2$, $t = 3$. $v=1+2*3=7$. But the options have A) 7.0 m/s. Wait, but let's check the calculation again.
Wait, $v=u+at=1.0\ m/s+(2.0\ m/s^{2}\times3.0\ s)=1 + 6=7.0\ m/s$.

Answer:

A) the object has constant velocity

Question 5