According to recent research, ice skaters are able to glide smoothly across the ice because ____

Helicopter blades withstand tremendous stresses. In addition to supporting the weight of a helicopter, they are spun at rapid ra

BabaBlast [244]

Explanation:

It is given that,

Length of the helicopter, l = 3.1 m

The helicopter rotates, the length of helicopter will become the radius of circular path, r = 3.1 m

Angular speed of the helicopter, $\omega=280\ rev/min=29.32\ rad/s$

(a) The centripetal acceleration in terms of angular velocity is given by :

$a_c=r\times \omega^2$

$a_c=3.1\times (29.32)^2$

$a_c=2664.95\ m/s^2$

(b) Let v is the linear speed of the tip. The relation between the linear and angular speed is given by :

$v=r\times \omega$

$v=3.1\times 29.32$

v = 90.89 m/s

$\dfrac{v_{tip}}{v_{sound}}=\dfrac{90.89}{340}=0.267$

Hence, this is the required solution.

4 0

3 years ago

Moving a charged object against an electrical force causes it to

Alinara [238K]

Decelerate

<u>Explanation:</u>

If a charged object is moving against an electric force, the electric force would cause the charged object to decelerate. Rate of deceleration would depend on the amount of the charge the object posses and amount of the opposing electric force.

This could be understood by visualising a hypothetical situation where a charged object is moving against an electric force. Since the object is charged, it would exert a force in its direction of motion which would be opposed by the electric force, thus causing it to decelerate

5 0

3 years ago

A 22-g bullet traveling 265 m/s penetrates a 1.9 kg block of wood and emerges going 125 m/s .

Usimov [2.4K]

The body moves at a velocity of 1.62m/s after the bullet emerges.

<h3>Given:</h3>

Mass of bullet, $m_1$ = 22g

= 0.022 kg

Mass of the block, $m_2$ = 1.9 kg

Velocity of bullet , $v_1$ = 265 m/s

$v_2 = 0$

According to the law of collision which states that the momentum of the body before the collision is equal to the momentum of the body after the collision.

After penetration;

$v^{'}_1 =125 m/s$