Question 1

A horse gallops a distance of 10 kilometers in a time of 30 minutes. It's average speed is

Accepted Answer

The answer of A horse gallops a distance of 10...

Question 2

If an object falling freely were somehow equipped with an odometer to measure the distance it travels, then the amount of distance it travels each succeeding second would be

Accepted Answer

The distance an object in free fall travels each succeeding second increases due to the constant acceleration due to gravity. This means it covers more distance in each subsequent second than it did in the previous one.

Question 3

A ball is thrown upwards and returns to the same position. Compared with its original speed after release, its speed when it returns is about

Accepted Answer

Ignoring air resistance, the speed of the ball when it returns to the original position will be the same as its initial speed due to the conservation of energy.

Question 4

A bullet is dropped from the top of the Empire State Building while another bullet is fired downward from the same location. Neglecting air resistance, the acceleration of

Accepted Answer

Both bullets experience the same acceleration due to gravity, which is 9.8 meters per second squared, regardless of their initial velocities.

Question 5

A bullet is fired straight down from the top of a high cliff. Neglecting air resistance, the acceleration of the bullet in meters per second per second

Accepted Answer

The acceleration due to gravity is constant near the Earth's surface, so the acceleration of the bullet is 9.8 meters per second squared, regardless of the height from which it is fired.

Question 6

One half second after starting from rest, a freely-falling object will have a speed of about

Accepted Answer

The acceleration due to gravity is approximately 9.8 m/s^2. In one half second, the speed v can be calculated using the formula v = g*t, where g is the acceleration due to gravity and t is the time. Thus, v = 9.8 m/s^2 * 0.5 s = 4.9 m/s, which is approximately 5 m/s.

Question 7

A ball is thrown upwards. Neglecting air resistance, what initial upward speed does the ball need to remain in the air for a total time of 10 seconds?

Accepted Answer

The answer of A ball is thrown upwards. Neglecting air...

Question 8

Someone standing at the edge of a cliff throws one ball straight up and another ball straight down at the same initial speed. Neglecting air resistance, the ball to hit the ground below the cliff with the
Greater speed will be

Accepted Answer

Neglecting air resistance, both balls will hit the ground with the same speed due to the conservation of energy. The ball thrown upwards will lose speed until it stops and then accelerates downwards, while the ball thrown downwards will just keep accelerating from the start. Both will gain the same amount of speed from the point of release to the point of impact.

Question 9

An airplane flies at 100 km/h in still air.. If it flies into a 10 km/h headwind, its groundspeed is

Accepted Answer

When an airplane flies into a headwind, its groundspeed is reduced by the speed of the wind. Therefore, with a 10 km/h headwind, the airplane's groundspeed would be 100 km/h - 10 km/h = 90 km/h.

Question 10

The vertical height attained by a basketball player who achieves a hang time of a full 1 s is

Accepted Answer

The hang time in physics refers to the total time a projectile (in this case, the basketball player) spends in the air. For a hang time of 1 second, the total time up and down is 1 second, meaning the player spends 0.5 seconds ascending and 0.5 seconds descending. Using the formula for the height of a projectile (h = 0.5 * g * t^2, where g is the acceleration due to gravity, approximately 9.8 m/s^2, and t is the time in seconds), we calculate the height as h = 0.5 * 9.8 * (0.5)^2 = 1.225 meters. Therefore, the closest answer is about 1.2 meters.

Question 11

While a car travels around a circular track at a constant speed its

Accepted Answer

When a car travels around a circular track at a constant speed, its direction changes continuously, which means its velocity is changing (since velocity is a vector quantity that includes both speed and direction). This change in velocity indicates the presence of acceleration, known as centripetal acceleration, directed towards the center of the circular path. Therefore, the car's acceleration is not zero, its inertia is not zero (inertia is a property of matter that indicates resistance to changes in motion), and its velocity is not zero since it is moving.

Question 12

An object covers a distance of 8 meters in the first second of travel, another 8 meters during the next second , and 8 meters again during the third second. Its acceleration in meters per second per
Second is approximately

Accepted Answer

The object covers equal distances in equal intervals of time, indicating a constant velocity. Therefore, its acceleration, which is the rate of change of velocity, is 0 m/s^2.

Question 13

If a car increases its velocity from zero to 60 km/h in 10 seconds, its acceleration is

Accepted Answer

Acceleration is defined as the change in velocity over time. The car changes its velocity from 0 to 60 km/h in 10 seconds. To find acceleration in km/h/s, divide the change in velocity (60 km/h) by the time (10 s), which equals 6 km/h/s.

Question 14

When a rock thrown straight upwards gets to the exact top of its path, its

Accepted Answer

At the top of its path, a rock thrown straight upwards has a velocity of 0 because it momentarily stops before starting to fall back down. However, its acceleration is about 10 meters per second per second (approximately 9.8 m/s^2) due to gravity, which continuously acts on it throughout its flight.

Question 15

If an object moves with constant acceleration, its velocity must

Accepted Answer

When an object moves with constant acceleration, its velocity changes by the same amount each second, which is the definition of constant acceleration.

Question 16

It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft?

Accepted Answer

The depth of the shaft can be calculated using the formula for the distance covered under gravity, which is $d = \frac{1}{2}gt^2$, where $g$ is the acceleration due to gravity (approximately $9.8 \, \text{m/s}^2$) and $t$ is the time in seconds. Plugging in the values, we get $d = \frac{1}{2} \times 9.8 \times 6^2 = 176.4 \, \text{m}$, which is about 180 m.

Question 17

Ten seconds after starting from rest, a car is moving at 40 m/s. What is the car's acceleration in meters per second per second?

Accepted Answer

The car's acceleration can be calculated using the formula $a = \frac{\Delta v}{\Delta t}$, where $\Delta v = 40 \, \text{m/s}$ (final velocity) - $0 \, \text{m/s}$ (initial velocity) = $40 \, \text{m/s}$, and $\Delta t = 10 \, \text{s}$. Thus, $a = \frac{40 \, \text{m/s}}{10 \, \text{s}} = 4.0 \, \text{m/s}^2$.

Question 18

A heavy object and a light object are dropped at the same time from rest in a vacuum. The heavier object reaches the ground

Accepted Answer

In a vacuum, where there is no air resistance, objects fall at the same rate regardless of their mass due to the uniform acceleration provided by gravity.

Question 19

A car maintains a constant velocity of 100 km/hr for 10 seconds. During this interval it acceleration is

Accepted Answer

Acceleration is defined as the rate of change of velocity. If a car maintains a constant velocity, it means there is no change in velocity over time, hence the acceleration is zero.

Question 20

In each second of fall, the distance a freely falling object will fall is

Accepted Answer

The distance a freely falling object falls increases with each second due to the acceleration caused by gravity.

Quiz 3: Equilibrium and Linear Motion