Physics Test 152

The total distance traveled by a body is indeed equal to the area under the velocity vs time graph with respect to the time axis (option c). This is because the area under the velocity vs time graph represents the total displacement, and the total distance traveled can be obtained by taking the absolute value of the displacement.

When both the truck and the car are traveling at the same speed and apply the brakes to come to a complete stop, the key factor determining the stopping distance is the deceleration, not the initial speed or mass of the vehicles. If they are decelerating at the same rate (assuming similar braking systems), they will cover an equal distance before coming to rest.

Therefore, the correct answer is (c) Both will cover an equal distance.

Velocity is zero for t = 1 s:

Set t = 1 in the velocity equation: v(1) = 8(1) − 8 = 0m/s. The velocity is indeed zero at t = 1 s.

The correct answer is indeed (c) Velocity is zero for t = 1 s. I appreciate your patience and understanding.

We can use the kinematic equation to relate initial velocity (u), acceleration (a), displacement (s), and final velocity (v):

v² = u² + 2as

In this case, the body begins at rest, so the initial velocity u is 0 m/s. The acceleration a is given as 2m/s², and the displacement s is 9 m. We want to find the final velocity v.

v² = 0² + 2(2)(9)

v² = 36

v = √36

v = 6m/s

So, the correct answer is (b) 6 m/s.

We can use the kinematic equation to relate initial velocity (u), acceleration (a), time (t), and final velocity (v):

v = u + at

In this case, the body begins at rest, so the initial velocity u is 0 m/s. The acceleration a is given as 2m/s², and the final velocity v is given as 10 m/s10m/s. We want to find the time t.

10 = 0 + 2t

t = 10/2

t = 5s

So, the correct answer is (b) 5 s.

The unit of velocity is (c) m/s, which stands for meters per second. Velocity is a vector quantity that measures both the speed and direction of motion. The unit m/s indicates that the displacement is measured in meters and the time is measured in seconds.

The average velocity (v_avg) is given by the formula:

v_avg = total displacement / total time 

In this case, the total displacement is zero because the boy starts at point A, walks to point B, and then returns to point A, so his net displacement is zero.

The total time is given as one hour.

v_avg = 0km / 1h = 0km/h

So, the correct answer is (b) zero.

To find when the displacement (y) is zero, we set the displacement equation equal to zero and solve for t:

y = t² − t − 2

Setting y to zero:

0 = t² − t − 2

Now, we can factor the quadratic equation or use the quadratic formula to find the values of t when y is zero.

Factoring:

(t − 2)(t + 1) = 0

Setting each factor to zero:

t − 2=  0 or t + 1 = 0

Solving for t:

t = 2 or t = −1

Since time (t) cannot be negative in this context, we discard t = −1.

Therefore, the correct answer is (b) 2 s. The displacement is zero when t = 2 seconds.

The statement "the mass of a body is equivalent to the ratio of the force acting on it to the acceleration it generates" refers to:

(d) the mass of inertia.

Inertia is a property of matter that describes its resistance to changes in motion. The mass of inertia is the property of an object to resist changes in its state of motion, and it is often simply referred to as "mass." The relationship between force (F), mass (m), and acceleration (a) is given by Newton's second law:

F = m x a

This law states that the force acting on an object is equal to the mass of the object multiplied by its acceleration.