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3 years ago

3 Select the correct answer. What is a substance?

Physics

1 answer:

USPshnik [31]3 years ago

5 0

Answer:

physical material from which something is made or which has discrete existence

Explanation:

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Which of the following simple machines is not properly identified? A. Scissors: lever B. Pizza cutter: wedge C. Screw: wheel and

GrogVix [38]

Pretty sure the answer is C. Screw: wheel and axle

8 0

3 years ago

When landing from a jump, a basketball player of mass 82 kg has a velocity of 1.2 m/s right before they hit the ground. The play

saw5 [17]

Answer:

2361.6N

Explanation:

Mass of player = 82kg

Velocity = 1.2m/s

Kinetic energy of player:

= 1/2mv²

= 1/2*82*1.2²

= 41x1.44

= 59.04J

Final kinetic energy = 0

Change in kinetic energy

|∆k| = |0-59.04|

= 59.04

Workdone by the feet = fd

d = 0.025

Fd = 59.04

F = 59.04/0.025

= 2361.6N

This is his average force.

6 0

3 years ago

Which statement is true about the atom?

slavikrds [6]

Answer:

Its d

atome contain

negative electrons,

positive protons and uncharged neutrons.

Explanation:

7 0

3 years ago

What is the relationship between the atoms of elements,its isotopes and its ions

klasskru [66]

An element refers to a collection of atoms having the same number of protons and electrons (an atomic number). In each element there is a different atomic number due to a different amount of protons in the nucleus.

An isotope is a variation of an element that contains a different number of neutrons, therefore adding weight to the atom.

An ion is a charged atom, and its charge shows how many electrons it needs to gain or lose in order to become stable.

6 0

3 years ago

For what angle of incidence at the first mirror will this ray strike the midpoint of the second mirror (which is 28.0 cmcm long)

loris [4]

This question is incomplete, the complete question is;

Two plane mirrors intersect at right angles. A laser beam strikes the first of them at a point 11.5 cm from their point of intersection, as shown in the figure.

For what angle of incidence at the first mirror will this ray strike the midpoint of the second mirror (which is 28.0 cmcm long) after reflecting from the first mirror

Answer: angle of incidence is 39.4°

Explanation:

Given that;

two plain mirrors intersect at right angle (90°)

distance d = 11.5 cm

S = 28.0 cm

Now the angle that the reflection ray males with first the mirror equal theta (∅)

tan∅ = (S/2) / d

tan∅ = (28/2) / 11.5

tan∅ = 14 / 11.5

tan∅ = 1.2173

∅ = tan⁻¹ (1.2173)

∅ = 50.6°

so angle of incidence = 90° - ∅

= 90° - 50.6°

= 39.4°

Therefore angle of incidence is 39.4°

5 0

3 years ago