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Helen [10]
3 years ago
12

An iron bal of mass 20kg is rolling on a flat surface. On applying force, the velocity change from 17ms to 27m/s in 5s. Calculat

e the magnitude of the force. (Ans:40N)
Physics
1 answer:
pentagon [3]3 years ago
4 0

Answer:

40 N

Explanation:

We first need to calculate the acceleration of the tron ball.

Since acceleration, a = (v - u)/t where u = initial velocity of iron ball = 17m/s, v = final velocity of iron ball = 27m/s and t = time taken for the change in velocity = 5 s.

So, a = (v - u)/t

= (27 m/s - 17 m/s)/5 s

= 10 m/s ÷ 5 s

= 2 m/s²

We know force on iron ball, F = ma where m = mass of iron ball = 20 kg and a = acceleration = 2 m/s²

So, F = ma

= 20 kg × 2 m/s²

= 40 kgm/s²

= 40 N

So, the magnitude of the force on the iron ball is 40 N.

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So here as we can see the fingers in the above case is curled such that in front position its showing towards right.

So the direction of magnetic field near the student in front position must be towards Right.

7 0
3 years ago
Read 2 more answers
If the average frequency emitted by a 160 W light bulb is 5.00 1014Hz and 10.0 of the input power is emitted as visible light ap
bearhunter [10]

Answer:

The value is \frac{n}{t}  = 4.83 *10^{19} \  photons / s

Explanation:

From the question we are told that

   The power rating of the bulb is  P = 160 \ W

   The frequency is f =  5.00 *10^{14} \ Hz

   The percentage of the input power that is emitted as visible light is \eta =  10\% = 0.10

   

Generally the amount of power emitted as visible light is mathematically represented as

       P_l =  0.10 * P_i

=>  P_l =  0.10 *160

=>  P_l =  16 \ W

Generally the amount of energy emitted as light is mathematically represented as

        E = n *  h  *  f

Here n is the number of photon ,  h is the Planks constant with value h =  6.625*10^{-34} \  J\cdot s

Generally this power emitted as visible light is mathematically represented as

   P_l = \frac{E}{t}

=>  P_l = \frac{E}{t} = \frac{nhf}{t}

=>  \frac{n}{t}  = \frac{P_l }{hf}

=>  \frac{n}{t}  = \frac{16 }{6.625 *10^{-34}* (5.00*10^{14})}

=>  \frac{n}{t}  = 4.83 *10^{19} \  photons / s

4 0
3 years ago
The critical angle for water is 49°. If a ray of light
Sonja [21]

Answer:

Snell's Law states

Ni sin i = Nr sin r

Judging from the question the source of the ray is in the water (directed up)

or NI = 1 / sin 49      Ni = 1.325 deg     the critical angle

From inside the pond:

Nr = 1.325 * sin 45 / 1 = 94 deg  

So refraction can occur  outside the pond and you do not have total internal refection.

 

3 0
3 years ago
Which of the balls will exert the smallest force on object A?Why
olganol [36]
The 1kg ball would exert the smallest force.

As force = mass x gravity, this means that the smaller the mass (kg), the lesser the force.

When the mass is lighter (1kg):

Force = mass x gravity
Force = 1 x 9.8
Force = 9.8N

Compared to when the mass is heavier (10kg)

Force = mass x gravity
Force = 10 x 9.8
Force = 98N

Where this proves that the lighter the mass, the smaller the force exerted.
6 0
3 years ago
A sprinter practicing for the 200-m dash accelerates uniformly from rest at A and reaches a top speed of 35 km/h at the 67-m mar
xz_007 [3.2K]

Answer:

0.705 m/s²

Explanation:

a) The sprinter accelerates uniformly from rest and reaches a top speed of 35 km/h at the 67-m mark.

Using newton's law of motion:

v² = u² + 2as

v = final velocity = 35 km/h = 9.72 m/s, u = initial velocity = 0 km/h,  s = distance = 67 m

9.72² = 0² + 2a(67)

134a = 94.484

a = 0.705 m/s²

b) The sprinter maintains this speed of 35 km/h for the next 88 meters. Therefore:

v = 35 km/h = 9.72 m/s, u = 35 km/h = 9.72 m/s, s = 88 m

v² = u² + 2as

9.72² = 9.72² + 2a(88)

176a = 9.72² - 9.72²

a = 0

c) During the last distance, the speed slows down from 35 km/h to 32 km/h.

u = 35 km/h = 9.72 m/s, v = 32 km/h = 8.89 m/s, s = 200 - (67 + 88) = 45 m

v² = u² + 2as

8.89² = 9.72² + 2a(45)

90a = 8.89² - 9.72²

90a = -15.4463

a = -0.1716 m/s²

The maximum acceleration is 0.705 m/s² which is from 0 to 67 m mark.

8 0
3 years ago
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