Noah en Meryem testen een zonnespiegel, zie de afbeelding. De spiegel bundelt de warmtestraling van de zon naar één punt. Op die plek hebben ze een zwarte pan met 2,0 kg water gezet. De oppervlakte van de spiegel is 3,0 m2. De warmtestraling van de zon is op een heldere zomerdag 1,0 kW m−2. De spiegel weerkaatst hiervan 80%. Norah en Meryem willen dat de temperatuur van het water met 80 °C stijgt. Neem aan dat het water 50% van alle warmtestraling die op de pan valt opneemt. De warmtecapaciteit van water is 4,18∙103 J kg−1 K−1.

Hoeveel minuten duurt dit opwarmen?

The sun’s mass is 2.0×10^ 30 kg, its radius is 7.0×10 5 km, and it has a rotational period of approximately 28 days. if the sun should collapse into a white dwarf of radius 3.5×10 3 km, what would its period be if no mass were ejected and a sphere of uniform density can model the sun both before and after?

Ain is , is 's of ? 0.62 0.79 1.27 1.50

3. a worker pushes a 30.5 kg polished stone along a polished table with a force on bonin a straight line for 5.20 s after starting from rest. there is no friction between thestone and the table. at the end of the table. the stone is hooked to a cable with a lengthof 62.0 cm to rotate it to a rough table to store until they can be picked up. the roughtable has a coefficient of static friction 0.702 with the polished stone. remember that 8= 9.80 m/s2a) what is the speed of the stone when it is hooked to the cable? b) what is the tension in the cable while the stone is rotating? (there is still nofriction)c) how much force is needed to make the stone begin sliding from rest on therough table? ius = 0.70262.0 cm30.5 kg20.5 kg6= 0