Why is “soft” iron used for the core of an electromagnet?

A boat loaded with a barrel of water floats in a swimming pool. When the water in the barrel is poured overboard, the swimming p

Lady bird [3.3K]

Answer: Remain unchanged

Explanation:

The boat with water barrel overboard floats in swimming pool when weight of the water displaced by the boat is equal to the buoyant force acting on the boat.

When the water in the barrel is poured overboard, the level of the swimming pool level would remain unchanged as the weight of the boat with the water and barrel would remain unchanged ( as the density and volume of the whole system remains same) and hence, the weight of the water (of the swimming pool) displaced by the boat would remain same.

A boat loaded with a barrel of water floats in a swimming pool. When the water in the barrel is poured overboard, the swimming pool level will remain unchanged. 

5 0

3 years ago

1. A 4-N force is used to move an object 2 m in 10 s. Which of the following is the power generated while moving the object?

guajiro [1.7K]

Power is the work done per unit time. Therefore,

$\begin{gathered} p=\frac{w}{t} \\ \text{where} \\ w=\text{work done} \\ t=\text{time} \end{gathered}$

Therefore,

$\begin{gathered} \text{work done=fd} \\ f=force=4N \\ d=\text{displacement}=2m \\ t=2\sec s \\ p=\frac{fd}{t}=\frac{4\times2}{10}=\frac{8}{10}=0.8watts \end{gathered}$

4 0

1 year ago

Which of these are scientific questions? Check all that apply. How will climate change affect forests? Which planet is the prett

Naddika [18.5K]

Answer:

The scientific questions here are:

a) How will climate change affect forests

b) How did life on Earth begin

c) Why did dinosaurs go extinct

Explanation:

Scientific question are logical quantifiable questions, whose answers can be measured. A good scientific question must have answers that can be tested by a carefully designed experiment or measurement. Some qualities like "prettiest" and "amazing" cannot be tested for nor are they measurable, and hence, they do not make a testable component of good scientific question.

6 0

3 years ago

All circuits include

valina [46]

Answer:

a battery, wires, and a switch.

Explanation:

All circuits include?

4 0

2 years ago

The driver of a car going 86.0 km/h suddenly sees the lights of a barrier 44.0 m ahead. It takes the driver 0.75 s to apply the

Lynna [10]

Part a

Answer: NO

We need to calculate the distance traveled once the brakes are applied. Then we would compare the distance traveled and distance of the barrier.

Using the second equation of motion:

$s=ut+0.5at^2$

where s is the distance traveled, u is the initial velocity, t is the time taken and a is the acceleration.

It is given that, u=86.0 km/h=23.9 m/s, t=0.75 s, $a=-10.0 m/s^2$

$\Rightarrow s=23.9 m/s \times 0.75s+0.5\times (-10.0 m/s^2)\times (0.75 s)^2=15.11 m$

Since there is sufficient distance between position where car would stop and the barrier, the car would not hit it.

Part b

Answer: 29.6 m/s

The maximum distance that car can travel is $s=44.0 m$

The acceleration is same, $a=-10.0 m/s^2$

The final velocity, v=0

Using the third equation of motion, we can find the maximum initial velocity for car to not hit the barrier:

$v^2-u^2=2as$

$0-u^2=-2 \time 10.0m/s^2 \times 44.0 m\Rightarrow u=\sqrt{880 m^2/s^2}=29.6 m/s$

Hence, the maximum speed at which car can travel and not hit the barrier is 29.6 m/s.

7 0

3 years ago