All categories

2 years ago

Elsa runs 100m. She takes 20s to run this distance. What is Elsa's average speed?

Physics

1 answer:

Ne4ueva [31]2 years ago

7 0

Answer:

Average speed = 5 m/s

Explanation:

Given the following data;

Distance = 100m

Time = 20 secs

To find the average speed;

Speed = distance/time

Substituting into the formula, we have;

Speed = 100/20

Speed = 5m/s

Therefore, Elsa's average speed is 5 meters per seconds.

You might be interested in

. While a person lifts a book of mass 2 kg from the floor to a tabletop, 1.5 m above the floor, how much work does the the perso

viktelen [127]

Answer:

a) 29.4 J

b) - 29.4 J

Explanation:

Given:

Mass of the book, m = 2 kg

Height above the floor, h = 1.5 m

Now,

the work done by the person will be = Force applied on the book × displacement of the book

thus,

Work done by the person = mg × h

where, g is the acceleration due to gravity

thus, on substituting the values, we get

Work done by the person = 2 × 9.8 × 1.5 = 29.4 J

now,

for the force applied by the gravitational pull (downwards) the displacement is in opposite direction (upwards) to the force of the gravity.

Thus,

work done by the gravity will be negative

therefore, the work done by the gravity = - mg × h

work done by the gravity = - 29.4 J

5 0

3 years ago

Read 2 more answers

Explain how a battery works. What are some possible materials you could use to make a battery for a circuit?

allochka39001 [22]

Answer:

Batteries are systems that store chemical energy and then release it as electrical energy when they are connected to a circuit. Batteries can be made from many materials, but they all share three main components: a metal anode, a metal cathode and an electrolyte between them. The electrolyte is an ionic solution that allows charge to flow through the system. When a load, such as a light bulb, is connected, an oxidation-reduction reaction occurs that releases electrons from the anode while the cathode gains electrons

Explanation:

4 0

3 years ago

ASK YOUR TEACHER A baseball with a mass of 146 g is thrown horizontally with a speed of 40.6 m/s (91 mi/h) at a bat. The ball is

RideAnS [48]

Answer:

Explanation:

mass of the ball = 146 g = 146 / 1000 = 0.146 kg

initial speed of the ball = 40.6 m/s

final speed of the ball = - 45.1 m/s

time of impact = 1.05 ms = 1.05 / 1000 = 0.00105 s

impulse, Ft = change in momentum = mv - mu = m (v-u)

F = m (v - u) / t = 0.146 kg ( -45.1 -40.6) / 0.00105 s = -11916.4 N

4 0

3 years ago

Classify the following situations into contact and non-contact forces.

NARA [144]

Answer: Contact force

a. Applying break in a vehicle.

d. The speed of ball rolling on ground is reduced

Non contact force

b. A coconut falling from a coconut tree.

c. The planets revolving around the sun.

Explanation:

The contact force is the force which exerts when one object or entity comes in contact with other object or entity. For example, on application of break the vehicle stops, the force is applied on the breaks to stop the vehicle. The ball rolling on the ground the speed reduces so the application of force on the ground also reduces.

The non contact force is the force one object exerts on the other without coming in direct contact with the other object. The force exerted by one object on other due to gravity is a non contact force. The coconut falling on the ground and planets revolving around the sun are examples of non contact force due to gravity.

8 0

2 years ago

An athlete in the early weeks of an aerobic training program develops a decreased hemoglobin concentration but does not report d

gizmo_the_mogwai [7]

Answer: B

Explanation: Hemoglobin is a protein in red blood cells that acts as the vehicle for oxygen and carbon dioxide from the lungs to tissues and vice-versa.

What is considered normal Hemoglobin levels vary throughout one's life, from childhood to adult life and in older adults. It even varies between women and men. In women, it also varies depending on whether they are pregnant or not.

When hemoglobin does become less than normal, it results in anemia, a condition accompanied by fatigue. Because the athlete does not have this symptom, he is not suffering from anemia, and so there is no cause for concern. Although the athlete's hemoglobin level has reduced, the absence of fatigue indicates that it is not lower than normal.

3 0

3 years ago